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 | 3 |
| 3 | 13 |
| 4 | 51 |
| 5 | 201 |
| 6 | 819 |
| 7 | 3382 |
| 8 | 14067 |
| 9 | 58927 |
| 10 | 248303 |
| 11 | 1051128 |
| 12 | 4466787 |
| 13 | 19043766 |
| 14 | 81418746 |
| 15 | 348936288 |
| 16 | 1498601459 |
| 17 | 6448162221 |
| 18 | 27791057997 |
| 19 | 119954739879 |
| 20 | 518451715551 |
| 21 | 2243481128020 |
| 22 | 9718784202240 |
| 23 | 42143960004750 |
| 24 | 182917942802595 |
| 25 | 794589638379576 |