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 | 4 |
| 1 | 14 |
| 2 | 60 |
| 3 | 310 |
| 4 | 1892 |
| 5 | 13374 |
| 6 | 107644 |
| 7 | 972710 |
| 8 | 9754500 |
| 9 | 107518702 |
| 10 | 1292197244 |
| 11 | 16818292374 |
| 12 | 235673103460 |
| 13 | 3537700674590 |
| 14 | 56637064388412 |
| 15 | 963304044932614 |
| 16 | 17346582063731204 |
| 17 | 329698807289999310 |
| 18 | 6595909863144795580 |
| 19 | 138548914038247276022 |
| 20 | 3048737440173364880484 |