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 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 55 |
| 4 | 274 |
| 5 | 1443 |
| 6 | 7905 |
| 7 | 44593 |
| 8 | 257305 |
| 9 | 1511553 |
| 10 | 9010170 |
| 11 | 54361486 |
| 12 | 331336454 |
| 13 | 2037132958 |
| 14 | 12619056108 |
| 15 | 78682008194 |
| 16 | 493427982703 |
| 17 | 3110202012353 |
| 18 | 19693920616872 |
| 19 | 125214061831251 |
| 20 | 799059649687239 |
| 21 | 5116372686471627 |
| 22 | 32860439054510610 |