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 | 0 |
| 2 | 3 |
| 3 | 14 |
| 4 | 45 |
| 5 | 146 |
| 6 | 537 |
| 7 | 1934 |
| 8 | 6861 |
| 9 | 24386 |
| 10 | 86913 |
| 11 | 309638 |
| 12 | 1102677 |
| 13 | 3927050 |
| 14 | 13986633 |
| 15 | 49814510 |
| 16 | 177416541 |
| 17 | 631877618 |
| 18 | 2250466449 |
| 19 | 8015156630 |
| 20 | 28546401765 |
| 21 | 101669514458 |
| 22 | 362101348953 |
| 23 | 1289643083966 |
| 24 | 4593131945709 |
| 25 | 16358681988674 |