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 | 6 |
| 2 | 40 |
| 3 | 268 |
| 4 | 1796 |
| 5 | 12036 |
| 6 | 80660 |
| 7 | 540548 |
| 8 | 3622516 |
| 9 | 24276516 |
| 10 | 162690580 |
| 11 | 1090281028 |
| 12 | 7306586036 |
| 13 | 48965540196 |
| 14 | 328145609300 |
| 15 | 2199088184708 |
| 16 | 14737326074356 |
| 17 | 98763106151076 |
| 18 | 661867090908820 |
| 19 | 4435543424059588 |
| 20 | 29725069786599476 |
| 21 | 199204401658077156 |