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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 50 |
| 4 | 254 |
| 5 | 1202 |
| 6 | 5774 |
| 7 | 27650 |
| 8 | 132494 |
| 9 | 634802 |
| 10 | 3041534 |
| 11 | 14572850 |
| 12 | 69822734 |
| 13 | 334540802 |
| 14 | 1602881294 |
| 15 | 7679865650 |
| 16 | 36796446974 |
| 17 | 176302369202 |
| 18 | 844715399054 |
| 19 | 4047274626050 |
| 20 | 19391657731214 |
| 21 | 92911014030002 |
| 22 | 445163412418814 |
| 23 | 2132906048064050 |
| 24 | 10219366827901454 |
| 25 | 48963928091443202 |