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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 20 |
| 7 | 51 |
| 8 | 184 |
| 9 | 550 |
| 10 | 2009 |
| 11 | 6487 |
| 12 | 23875 |
| 13 | 81724 |
| 14 | 302954 |
| 15 | 1078409 |
| 16 | 4034373 |
| 17 | 14771551 |
| 18 | 55789188 |
| 19 | 208526682 |
| 20 | 794933818 |
| 21 | 3017839193 |
| 22 | 11604938152 |
| 23 | 44590911769 |
| 24 | 172833268057 |
| 25 | 670520982414 |
| 26 | 2617397888002 |
| 27 | 10234831661388 |
| 28 | 40204487779050 |
| 29 | 158254659096516 |
| 30 | 625142808049902 |