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 | 2 |
| 1 | 4 |
| 2 | 12 |
| 3 | 44 |
| 4 | 180 |
| 5 | 788 |
| 6 | 3612 |
| 7 | 17116 |
| 8 | 83172 |
| 9 | 412196 |
| 10 | 2075436 |
| 11 | 10586892 |
| 12 | 54595476 |
| 13 | 284157492 |
| 14 | 1490774076 |
| 15 | 7875206076 |
| 16 | 41854313412 |
| 17 | 223636052036 |
| 18 | 1200637707852 |
| 19 | 6473448634348 |
| 20 | 35037238641780 |
| 21 | 190299310403924 |
| 22 | 1036863750837852 |
| 23 | 5665846701859484 |
| 24 | 31042935297750180 |
| 25 | 170499885177942628 |