oeis-validator 0.1.0

Validate OEIS draft entries against the internal format specification and style sheet

oeis-validator

Validate OEIS entries against the internal format specification and style sheet. Parses .txt files in OEIS internal format and checks all 19 field tags for compliance, consistency, and style adherence.

Features

• All 19 field tags — %I, %S, %N, %C, %D, %F, %H, %I, %K, %L, %M, %N, %O, %P, %R, %S, %T, %U, %Y
• 30 keyword checks — validates %K against the official keyword list
• 14 style patterns — catches common OEIS style-sheet violations: counts the number of, greater or equal, less or equal, couples of, respectfully, triplets of, amount of, fulfills, allows to, except (missing for), unique vs distinct, its vs it's, p(n) ambiguity, be integer (missing article)
• Non-ASCII detection — rejects stray Unicode in data/keyword fields
• Reference cross-checks — URLs in %D, duplicate A-numbers in %Y, b-file ordering in %H, a_n/a[n] notation in %F
• Program validation — missing language labels in %o, unsigned programs
• CLI modes — file input, stdin, --demo, --coverage
• Adversarial resilience — null bytes, BOM, mixed line endings, RTL overrides, shell injection attempts, binary input, 50-entry bulk parsing
• Zero dependencies — pure Python stdlib

Install

pip install oeis-validator

Usage

# Validate a file
oeis-validator entry.txt

# Validate from stdin
echo '%I A000001 %S A000001 1,1,2,3,5' | oeis-validator

# Run built-in demos (good entry, bad entry, multi-entry)
oeis-validator --demo

# Show rule coverage table
oeis-validator --coverage

API

from oeis_validator import parse_entry, validate, report

entry = parse_entry(text)
issues = validate(entry)
exit_code = report(entry, issues)

Real-world validation

The data/ directory contains 10 real OEIS sequences fetched from the OEIS server. The validator produces 0 ERROR-level issues on all of them. Each warning is cross-checked against the official style sheet (.oeis_style_sheet.txt):

Sequence	Warnings	Fields warned
A000005 (divisors)	24	%o
A000010 (totient)	12	%o, %H
A000040 (primes)	28	%o, %D, %H, %Y
A000041 (partitions)	50	%o, %H
A000045 (Fibonacci)	49	%o, %H, %Y
A000108 (Catalan)	30	%o, %H, %F
A000203 (sigma)	16	%o, %H, %Y
A000217 (triangular)	16	%o, %Y
A000290 (squares)	4	%o, %Y
A001222 (Omega)	14	%o

Development

git clone https://github.com/daedalus/oeis_validator.git
cd oeis_validator
pip install -e ".[test]"

# run tests (218+ passing)
pytest -v

# format
ruff format src/ tests/

# lint + type check
prospector --with-tool ruff --with-tool mypy src/
semgrep --config=auto --severity=ERROR src/

# find unused code
vulture --min-confidence 90 src/

Threat model (adversarial tests)

The test suite (tests/test_adversarial.py) validates the parser and validator against 52 adversarial scenarios across six categories:

Category	Examples
Parser	Null bytes, BOM, mixed \r\n/\n, RTL overrides, HTML injection, shell injection, 100-term sequences, negative zero, 50 repeated %S lines
Rules	Mixed valid/invalid keywords, contradictory keyword pairs, offset > sequence length, 100 cross-references with duplicates, fake language labels, URL-free references
Style	Case-variant pattern matching, false-positive avoidance for except for/its/p(n) in formulas
CLI	Binary input, empty stdin, large stdin, directory as file, weird filenames, unknown flags, multiple file args
Multi-entry	50-entry bulk parse, mixed keyword sets per entry
Regression	Warning-count snapshots per data file, style-sheet field whitelist