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 | 1 |
| 2 | 7 |
| 3 | 23 |
| 4 | 153 |
| 5 | 849 |
| 6 | 6128 |
| 7 | 43534 |
| 8 | 319119 |
| 9 | 2255466 |
| 10 | 15307395 |
| 11 | 98349144 |
| 12 | 597543497 |
| 13 | 3430839916 |
| 14 | 18653684881 |
| 15 | 96273409815 |
| 16 | 473010823993 |
| 17 | 2218614773950 |
| 18 | 9961651259869 |
| 19 | 42927432229913 |
| 20 | 177963663264430 |