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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 20 |
| 5 | 59 |
| 6 | 184 |
| 7 | 593 |
| 8 | 1964 |
| 9 | 6642 |
| 10 | 22845 |
| 11 | 79667 |
| 12 | 281037 |
| 13 | 1001092 |
| 14 | 3595865 |
| 15 | 13009673 |
| 16 | 47366251 |
| 17 | 173415176 |
| 18 | 638044203 |
| 19 | 2357941142 |
| 20 | 8748646386 |
| 21 | 32576869203 |
| 22 | 121701491701 |
| 23 | 456012458965 |
| 24 | 1713339737086 |
| 25 | 6453584646837 |
| 26 | 24364925260024 |
| 27 | 92185136438942 |