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 | 3 |
| 3 | 12 |
| 4 | 52 |
| 5 | 236 |
| 6 | 1109 |
| 7 | 5366 |
| 8 | 26639 |
| 9 | 135300 |
| 10 | 701269 |
| 11 | 3700400 |
| 12 | 19834973 |
| 13 | 107784622 |
| 14 | 592705377 |
| 15 | 3292970302 |
| 16 | 18458954896 |
| 17 | 104276682820 |
| 18 | 593056996445 |
| 19 | 3392898090908 |
| 20 | 19512100041995 |
| 21 | 112729617387020 |
| 22 | 653965783541960 |
| 23 | 3807766434556940 |