Local copy of the On-Line Encyclopedia of Integer Sequences¶
The SloaneEncyclopedia object provides access to a local copy of the database
containing only the sequences and their names. To use this, you must download
and install the database using SloaneEncyclopedia.install(), or
SloaneEncyclopedia.install_from_gz() if you have already downloaded the
database manually.
To look up a sequence, type
sage: SloaneEncyclopedia[60843]  # optional - sloane_database
[1, 6, 21, 107, 47176870]
>>> from sage.all import *
>>> SloaneEncyclopedia[Integer(60843)]  # optional - sloane_database
[1, 6, 21, 107, 47176870]
To get the name of a sequence, type
sage: SloaneEncyclopedia.sequence_name(1)  # optional - sloane_database
'Number of groups of order n.'
>>> from sage.all import *
>>> SloaneEncyclopedia.sequence_name(Integer(1))  # optional - sloane_database
'Number of groups of order n.'
To search locally for a particular subsequence, type
sage: SloaneEncyclopedia.find([1,2,3,4,5], 1)    # optional - sloane_database
[(15, [1, 2, 3, 4, 5, 7, 7, 8, 9, 11, 11, 13, 13, 16, 16, 16, 17, 19, 19, 23, 23, 23, 23, 25, 25, 27, 27, 29, 29, 31, 31, 32, 37, 37, 37, 37, 37, 41, 41, 41, 41, 43, 43, 47, 47, 47, 47, 49, 49, 53, 53, 53, 53, 59, 59, 59, 59, 59, 59, 61, 61, 64, 64, 64, 67, 67, 67, 71, 71, 71, 71, 73])]
>>> from sage.all import *
>>> SloaneEncyclopedia.find([Integer(1),Integer(2),Integer(3),Integer(4),Integer(5)], Integer(1))    # optional - sloane_database
[(15, [1, 2, 3, 4, 5, 7, 7, 8, 9, 11, 11, 13, 13, 16, 16, 16, 17, 19, 19, 23, 23, 23, 23, 25, 25, 27, 27, 29, 29, 31, 31, 32, 37, 37, 37, 37, 37, 41, 41, 41, 41, 43, 43, 47, 47, 47, 47, 49, 49, 53, 53, 53, 53, 59, 59, 59, 59, 59, 59, 61, 61, 64, 64, 64, 67, 67, 67, 71, 71, 71, 71, 73])]
The default maximum number of results is 30, but to return up to 100, type
sage: SloaneEncyclopedia.find([1,2,3,4,5], 100)  # optional - sloane_database
[(15, [1, 2, 3, 4, 5, 7, 7, 8, 9, 11, 11, ...
>>> from sage.all import *
>>> SloaneEncyclopedia.find([Integer(1),Integer(2),Integer(3),Integer(4),Integer(5)], Integer(100))  # optional - sloane_database
[(15, [1, 2, 3, 4, 5, 7, 7, 8, 9, 11, 11, ...
Results in either case are of the form [ (number, list) ].
See also
- If you want to get more informations relative to a sequence (references, links, examples, programs, …), you can use the On-Line Encyclopedia of Integer Sequences provided by the - OEISmodule.
- Some infinite OEIS sequences are implemented in Sage, via the - sloane_functionsmodule.
AUTHORS:
- Steven Sivek (2005-12-22): first version 
- Steven Sivek (2006-02-07): updated to correctly handle the new search form on the Sloane website, and it is now also smarter about loading the local database in that it does not convert a sequence from string form to a list of integers until absolutely necessary. This seems to cut the loading time roughly in half. 
- Steven Sivek (2009-12-22): added the SloaneEncyclopedia functions install() and install_from_gz() so users can get the latest versions of the OEIS without having to get an updated spkg; added sequence_name() to return the description of a sequence; and changed the data type for elements of each sequence from int to Integer. 
- Thierry Monteil (2012-02-10): deprecated dead code and update related doc and tests. 
- class sage.databases.sloane.SloaneEncyclopediaClass[source]¶
- Bases: - object- A local copy of the Sloane Online Encyclopedia of Integer Sequences that contains only the sequence numbers and the sequences themselves. - find(seq, maxresults=30)[source]¶
- Return a list of all sequences which have seq as a subsequence, up to maxresults results. Sequences are returned in the form (number, list). - INPUT: - seq– list
- maxresults– integer
 - OUTPUT: list of 2-tuples (i, v), where v is a sequence with seq as a subsequence. 
 - install(oeis_url='https://oeis.org/stripped.gz', names_url='https://oeis.org/names.gz', overwrite=False)[source]¶
- Download and install the online encyclopedia, raising an IOError if either step fails. - INPUT: - oeis_url– string (default:- 'https://oeis.org...') The URL of the stripped.gz encyclopedia file
- names_url– string (default:- 'https://oeis.org...') The URL of the names.gz encyclopedia file. If you do not want to download this file, set names_url=None.
- overwrite– boolean (default:- False); if the encyclopedia is already installed and overwrite=True, download and install the latest version over the installed one
 
 - install_from_gz(stripped_file, names_file, overwrite=False)[source]¶
- Install the online encyclopedia from a local stripped.gz file. - INPUT: - stripped_file– string; the name of the stripped.gz OEIS file
- names_file– string; the name of the names.gz OEIS file, or None if the user does not want it installed
- overwrite– boolean (default:- False); if the encyclopedia is already installed and- overwrite=True, install ‘filename’ over the old encyclopedia
 
 - is_installed()[source]¶
- Check if a local copy of the encyclopedia is installed. - EXAMPLES: - sage: SloaneEncyclopedia.is_installed() # optional - sloane_database True - >>> from sage.all import * >>> SloaneEncyclopedia.is_installed() # optional - sloane_database True 
 - load()[source]¶
- Load the entire encyclopedia into memory from a file. This is done automatically if the user tries to perform a lookup or a search. 
 - sequence_name(N)[source]¶
- Return the name of sequence - Nin the encyclopedia.- If sequence - Ndoes not exist, return- ''. If the names database is not installed, raise an- IOError.- INPUT: - N– integer
 - OUTPUT: string - EXAMPLES: - sage: SloaneEncyclopedia.sequence_name(1) # optional - sloane_database 'Number of groups of order n.' - >>> from sage.all import * >>> SloaneEncyclopedia.sequence_name(Integer(1)) # optional - sloane_database 'Number of groups of order n.' 
 
- sage.databases.sloane.copy_gz_file(gz_source, bz_destination)[source]¶
- Decompress a gzipped file and install the bzipped version. - This is used by SloaneEncyclopedia.install_from_gz to install several gzipped OEIS database files. - INPUT: - gz_source– string; the name of the gzipped file
- bz_destination– string; the name of the newly compressed file