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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 48 |
| 5 | 165 |
| 6 | 572 |
| 7 | 2002 |
| 8 | 7072 |
| 9 | 25194 |
| 10 | 90440 |
| 11 | 326876 |
| 12 | 1188640 |
| 13 | 4345965 |
| 14 | 15967980 |
| 15 | 58929450 |
| 16 | 218349120 |
| 17 | 811985790 |
| 18 | 3029594040 |
| 19 | 11338026180 |
| 20 | 42550029600 |
| 21 | 160094486370 |
| 22 | 603784920024 |
| 23 | 2282138106804 |
| 24 | 8643460269248 |