This repository contains scripts to download, process, and analyze data from the Online Encyclopedia of Integer Sequences (OEIS), as hosted on http://www.oeis.org.
Our tools handle OEIS data from three sources:
- remote: the OEIS database residing on the oeis.org server. The remote database can be accessed via HTTP or HTTPS requests.
- local sqlite3: a replica of the remote database as a local SQLite3 database file.
- local pickle: the OEIS database a a local pickle-format file, used for local analysis. The "pickle" format is Python-specific.
The local sqlite3 database is obtained from the remote database by an automatic web-crawler called 'fetch_oeis_database.py'. It contains the sequence metadata in the internal format as it is used on the remote side, as well as so called 'b-file' data that contain sequence data a(n) up to high values of n.
The local pickle format database is obtained from the local_sqlite3 database by parsing the data and turning it into OeisEntry instances. The pickled list of all OeisEntry instances can be read in its entirety within a few seconds.
Apart from these sources that describe the OEIS data, we also use the "catalog", which is a Python module that contains implementations of sequence generating functions.
- All code is written in Python 3.
- Some code depends on the 'numpy' library:
- show_database_time.py
- solve_linear_sequence.py
- Some code depends on the 'matplotlib' library:
- show_database_time.py
Non-Python files:
| filename | description |
|---|---|
| README.md | Text file (markdown format) description of the project. |
| catalog_files/*.json | Catalog files, describing parametrized sequence generating functions. |
Python scripts files:
| filename | description |
|---|---|
| fetch_oeis_database.py | Fetch and refresh data from the remote OEIS database to a local sqlite3 database. |
| show_database_time.py | Visualize time stamps in a given local sqlite3 OEIS database. |
| parse_oeis_database.py | Parse a local sqlite3 database and produce a local pickle database. |
| find_sequences.py | Probe a local pickle database for a given sequence (work in progress). |
| pickle_to_json.py | Read a local pickle database and write a JSON version. |
| solve_linear_sequence.py | Find linear sequences in a local 'pickle' database. |
| check_database.py | Perform a number of checks on the data in a local pickle database. |
| verify_oeis_catalog.py | Verify the catalog. |
Python modules:
| filename | description |
|---|---|
| fraction_based_linear_algebra.py | Perform matrix inversion without loss of precision using the Fraction type. |
| charmap.py | Defines lists of acceptable characters for the OEIS directives. |
| OeisEntry.py | Defines a simple class that contains (most of) the data of a single OEIS sequence. |
| timer.py | Simplifies timing lengthy operations using a context manager. |
| fetch_remote_oeis_entry.py | Fetches a single sequence's data from the OEIS website (www.oeis.org). |
| catalog.py | Access the local catalog. |
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