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 | 19 |
| 2 | 89 |
| 3 | 331 |
| 4 | 1437 |
| 5 | 6289 |
| 6 | 28241 |
| 7 | 128413 |
| 8 | 590197 |
| 9 | 2734297 |
| 10 | 12749679 |
| 11 | 59763613 |
| 12 | 281370909 |
| 13 | 1329632401 |
| 14 | 6303226767 |
| 15 | 29963180101 |
| 16 | 142776168261 |
| 17 | 681776377177 |
| 18 | 3261689820791 |
| 19 | 15630400760077 |
| 20 | 75015245736567 |
| 21 | 360509440244557 |