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 | 2 |
| 2 | 90 |
| 3 | 2252 |
| 4 | 39500 |
| 5 | 535502 |
| 6 | 5930022 |
| 7 | 55599992 |
| 8 | 452715672 |
| 9 | 3262336002 |
| 10 | 21114177018 |
| 11 | 124188986196 |
| 12 | 670283877588 |
| 13 | 3346707628446 |
| 14 | 15564971674518 |
| 15 | 67830161708592 |
| 16 | 278406848295312 |
| 17 | 1081149205136382 |
| 18 | 3988232552194662 |
| 19 | 14025412751733092 |
| 20 | 47171740235162340 |