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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 16 |
| 5 | 58 |
| 6 | 220 |
| 7 | 821 |
| 8 | 3090 |
| 9 | 11743 |
| 10 | 44792 |
| 11 | 171495 |
| 12 | 659051 |
| 13 | 2540116 |
| 14 | 9814642 |
| 15 | 38007320 |
| 16 | 147472450 |
| 17 | 573200298 |
| 18 | 2231386904 |
| 19 | 8698569320 |
| 20 | 33952074197 |
| 21 | 132672190652 |
| 22 | 518973027214 |
| 23 | 2031995088017 |
| 24 | 7963057824045 |
| 25 | 31231061046115 |