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 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 13 |
| 6 | 35 |
| 7 | 85 |
| 8 | 257 |
| 9 | 765 |
| 10 | 2518 |
| 11 | 8359 |
| 12 | 28968 |
| 13 | 101340 |
| 14 | 361270 |
| 15 | 1297879 |
| 16 | 4707969 |
| 17 | 17179435 |
| 18 | 63068876 |
| 19 | 232615771 |
| 20 | 861725794 |
| 21 | 3204236779 |
| 22 | 11955836258 |
| 23 | 44748176653 |
| 24 | 167959144032 |
| 25 | 632058070310 |
| 26 | 2384235077576 |
| 27 | 9013628451275 |