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 | 1 |
| 1 | 3 |
| 2 | 14 |
| 3 | 69 |
| 4 | 344 |
| 5 | 1721 |
| 6 | 8621 |
| 7 | 43206 |
| 8 | 216570 |
| 9 | 1085574 |
| 10 | 5441294 |
| 11 | 27272044 |
| 12 | 136679882 |
| 13 | 684959516 |
| 14 | 3432431414 |
| 15 | 17199626276 |
| 16 | 86182614207 |
| 17 | 431824008713 |
| 18 | 2163629549132 |
| 19 | 10840520569183 |
| 20 | 54313805146415 |
| 21 | 272122594209738 |
| 22 | 1363372115057995 |
| 23 | 6830627007245263 |