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 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 51 |
| 6 | 187 |
| 7 | 715 |
| 8 | 2800 |
| 9 | 11138 |
| 10 | 44846 |
| 11 | 182476 |
| 12 | 749566 |
| 13 | 3105575 |
| 14 | 12966165 |
| 15 | 54505650 |
| 16 | 230508612 |
| 17 | 980045835 |
| 18 | 4186600220 |
| 19 | 17960356014 |
| 20 | 77343359518 |
| 21 | 334217730014 |
| 22 | 1448771849516 |
| 23 | 6298222363395 |
| 24 | 27452466169243 |
| 25 | 119949953637406 |
| 26 | 525284132440963 |