This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 7 |
| 6 | 21 |
| 7 | 61 |
| 8 | 187 |
| 9 | 577 |
| 10 | 1825 |
| 11 | 5831 |
| 12 | 18883 |
| 13 | 61699 |
| 14 | 203429 |
| 15 | 675545 |
| 16 | 2258291 |
| 17 | 7592249 |
| 18 | 25656477 |
| 19 | 87096661 |
| 20 | 296891287 |
| 21 | 1015797379 |
| 22 | 3487272317 |
| 23 | 12008898531 |
| 24 | 41471260883 |
| 25 | 143588078449 |
| 26 | 498343911529 |
| 27 | 1733410858955 |
| 28 | 6041795275027 |
| 29 | 21098924740155 |