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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 40 |
| 6 | 197 |
| 7 | 980 |
| 8 | 5142 |
| 9 | 27632 |
| 10 | 152191 |
| 11 | 853564 |
| 12 | 4863492 |
| 13 | 28075992 |
| 14 | 163920550 |
| 15 | 966421928 |
| 16 | 5746596806 |
| 17 | 34428962746 |
| 18 | 207654949801 |
| 19 | 1259963104618 |
| 20 | 7686160299232 |
| 21 | 47116518171284 |
| 22 | 290105437233107 |
| 23 | 1793451033655758 |