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 | 10 |
| 3 | 143 |
| 4 | 1988 |
| 5 | 27693 |
| 6 | 385710 |
| 7 | 5372251 |
| 8 | 74825800 |
| 9 | 1042188953 |
| 10 | 14515819538 |
| 11 | 202179284583 |
| 12 | 2815994164620 |
| 13 | 39221739020101 |
| 14 | 546288352116790 |
| 15 | 7608815190614963 |
| 16 | 105977124316492688 |
| 17 | 1476070925240282673 |
| 18 | 20559015829047464730 |
| 19 | 286350150681424223551 |