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 | 5 |
| 3 | 23 |
| 4 | 108 |
| 5 | 574 |
| 6 | 3553 |
| 7 | 25451 |
| 8 | 207744 |
| 9 | 1904010 |
| 10 | 19357873 |
| 11 | 216180227 |
| 12 | 2630384900 |
| 13 | 34634700918 |
| 14 | 490653944569 |
| 15 | 7441157228467 |
| 16 | 120286142846816 |
| 17 | 2064606497134554 |
| 18 | 37499986847250777 |
| 19 | 718589662860007003 |
| 20 | 14487877657131343316 |