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 | 5 |
| 3 | 43 |
| 4 | 515 |
| 5 | 7950 |
| 6 | 150086 |
| 7 | 3349945 |
| 8 | 86296849 |
| 9 | 2519907605 |
| 10 | 82249222661 |
| 11 | 2967449372028 |
| 12 | 117266100841668 |
| 13 | 5037282382077353 |
| 14 | 233701540415817409 |
| 15 | 11645959855678136519 |
| 16 | 620389246928233860127 |
| 17 | 35181554115178393462386 |
| 18 | 2116059351692554708911298 |