---
license: cc0-1.0
pretty_name: "Integer Sequences"
tags:
  - mathematics
  - integers
  - sequences
  - primes
  - combinatorics
  - number-theory
---

# Integer Sequences

Many integer sequences as one-value-per-line CSV files.
Generated from formulas, recurrences, sieves, and filters.
Primes sourced from https://t5k.org.

## Contents

Each file in `base/` holds one sequence, one integer per line,
sorted ascending.

### Figurate and geometric

- `triangular`, `pentagonal`, `hexagonal`, `heptagonal`, `star`
- `pow-2`, `pow-3`, `pow-5`, `pow-7`
- `tetrahedral`, `pentatope`, `octahedral`
- `square-pyramidal`, `stella-octangula`
- `icosahedral`, `dodecahedral`, `rhombic-dodecahedral`
- `truncated-tetrahedral`, `truncated-octahedral`, `truncated-cube`
- `centered-triangular`, `centered-square`, `centered-pentagonal`,
  `centered-hexagonal`, `centered-heptagonal`, `centered-octagonal`,
  `centered-decagonal`
- `N-gonal-pyramidal` (3 through 20)
- `N-centered-polygonal` (3 through 11)
- `pronic`

### Recurrence-based

- `fibonacci`, `lucas`, `padovan`, `tribonacci`, `pell`, `jacobsthal`
- `catalan`, `bell`, `motzkin`, `delannoy`, `derangement`
- `partition`, `planar-partitions`
- `euler-number`, `stirling-second`
- `look-and-say`, `sylvester`, `recaman`, `stern-brocot`

### Prime and factoring

- `prime` (50 million, from t5k.org)
- `twin-prime`, `safe-prime`, `sophie-germain-prime`, `super-prime`
- `semiprime`, `sphenic`, `composite`
- `square-free`, `powerful`
- `primorial`

### Digit and filter

- `palindromic`, `happy`, `harshad`, `abundant`, `deficient`
- `binary-even` (evil numbers), `smith`, `lucky`
- `undulating`, `narcissistic`, `automorphic`, `kaprekar`
- `collatz-length`, `euler-totient`, `divisors`

### Other

- `natural`, `n-eq-3-mod-4`, `factorial`, `repunit`
- `binary-base-tree` (Wedderburn-Etherington)
- `highly-composite`, `amicable`
- Static lookups: `perfect`, `weird`, `order-of-simple-groups`,
  `connected-planar-graph`, `number-of-connected-graphs`,
  `planar-graph`, `irreducible-polynomials`

## Sources

- **The Prime Pages (t5k.org)**: https://t5k.org/lists/small/millions/
- **OEIS**: https://oeis.org (reference for sequence definitions)

## License

CC0-1.0. The sequences are mathematical facts, not creative works.