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 | 4 |
| 2 | 24 |
| 3 | 143 |
| 4 | 881 |
| 5 | 5534 |
| 6 | 35213 |
| 7 | 226238 |
| 8 | 1464382 |
| 9 | 9534594 |
| 10 | 62377881 |
| 11 | 409717004 |
| 12 | 2700168229 |
| 13 | 17845927498 |
| 14 | 118238842174 |
| 15 | 785086422265 |
| 16 | 5222747607607 |
| 17 | 34802614713382 |
| 18 | 232261844100109 |
| 19 | 1552139710253683 |
| 20 | 10385180872126402 |
| 21 | 69563083672190704 |
| 22 | 466425975579323539 |