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 | 3 |
| 2 | 10 |
| 3 | 40 |
| 4 | 160 |
| 5 | 670 |
| 6 | 3001 |
| 7 | 13503 |
| 8 | 60408 |
| 9 | 270370 |
| 10 | 1192385 |
| 11 | 5221700 |
| 12 | 23404787 |
| 13 | 108379668 |
| 14 | 507618711 |
| 15 | 2353392292 |
| 16 | 10735523052 |
| 17 | 48337299889 |
| 18 | 216062343583 |
| 19 | 966793284879 |
| 20 | 4375808357962 |
| 21 | 20209591137998 |
| 22 | 95483805098650 |