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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 22 |
| 7 | 76 |
| 8 | 271 |
| 9 | 1001 |
| 10 | 3765 |
| 11 | 14381 |
| 12 | 55450 |
| 13 | 214880 |
| 14 | 835663 |
| 15 | 3255652 |
| 16 | 12698352 |
| 17 | 49559793 |
| 18 | 193513944 |
| 19 | 755852101 |
| 20 | 2953214386 |
| 21 | 11541989533 |
| 22 | 45123241746 |
| 23 | 176465152051 |
| 24 | 690340349398 |
| 25 | 2701579878022 |
| 26 | 10576116931462 |
| 27 | 41418132927403 |
| 28 | 162259989848094 |
| 29 | 635899817853002 |
| 30 | 2492993368347594 |