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 | 4 |
| 2 | 17 |
| 3 | 74 |
| 4 | 325 |
| 5 | 1432 |
| 6 | 6317 |
| 7 | 27878 |
| 8 | 123049 |
| 9 | 543148 |
| 10 | 2397545 |
| 11 | 10583234 |
| 12 | 46716589 |
| 13 | 206216896 |
| 14 | 910285253 |
| 15 | 4018193246 |
| 16 | 17737162705 |
| 17 | 78295623508 |
| 18 | 345613602113 |
| 19 | 1525612248122 |
| 20 | 6734378273941 |
| 21 | 29726983906792 |
| 22 | 131221255523165 |