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 | 6 |
| 2 | 26 |
| 3 | 111 |
| 4 | 506 |
| 5 | 2437 |
| 6 | 12118 |
| 7 | 61499 |
| 8 | 317485 |
| 9 | 1666371 |
| 10 | 8891543 |
| 11 | 48221602 |
| 12 | 265708512 |
| 13 | 1486905853 |
| 14 | 8446728295 |
| 15 | 48690214869 |
| 16 | 284692228671 |
| 17 | 1687855348715 |
| 18 | 10143257898587 |
| 19 | 61768997909283 |
| 20 | 381059689323080 |
| 21 | 2380852983417944 |