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 | 28 |
| 4 | 171 |
| 5 | 1113 |
| 6 | 7590 |
| 7 | 53588 |
| 8 | 388519 |
| 9 | 2876003 |
| 10 | 21648065 |
| 11 | 165193576 |
| 12 | 1275043280 |
| 13 | 9936953788 |
| 14 | 78087083456 |
| 15 | 618049278976 |
| 16 | 4922606097263 |
| 17 | 39425205882007 |
| 18 | 317316076325015 |
| 19 | 2565216211152700 |
| 20 | 20819872339143179 |
| 21 | 169586043613302169 |
| 22 | 1385856599443533442 |