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 | 2 |
| 2 | 15 |
| 3 | 184 |
| 4 | 2381 |
| 5 | 30942 |
| 6 | 402235 |
| 7 | 5229044 |
| 8 | 67977561 |
| 9 | 883708282 |
| 10 | 11488207655 |
| 11 | 149346699504 |
| 12 | 1941507093541 |
| 13 | 25239592216022 |
| 14 | 328114698808275 |
| 15 | 4265491084507564 |
| 16 | 55451384098598321 |
| 17 | 720867993281778162 |
| 18 | 9371283912663116095 |
| 19 | 121826690864620509224 |
| 20 | 1583746981240066619901 |