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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 15 |
| 6 | 42 |
| 7 | 120 |
| 8 | 338 |
| 9 | 952 |
| 10 | 2671 |
| 11 | 7494 |
| 12 | 21035 |
| 13 | 59115 |
| 14 | 166432 |
| 15 | 469560 |
| 16 | 1327802 |
| 17 | 3763545 |
| 18 | 10692500 |
| 19 | 30447858 |
| 20 | 86894361 |
| 21 | 248506757 |
| 22 | 712109662 |
| 23 | 2044402512 |
| 24 | 5879579540 |
| 25 | 16937048040 |
| 26 | 48864612667 |
| 27 | 141179970820 |
| 28 | 408444645375 |
| 29 | 1183143522435 |
| 30 | 3431241484224 |
| 31 | 9961919944284 |