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 | 5 |
| 2 | 17 |
| 3 | 53 |
| 4 | 153 |
| 5 | 421 |
| 6 | 1125 |
| 7 | 2937 |
| 8 | 7537 |
| 9 | 19093 |
| 10 | 47881 |
| 11 | 119133 |
| 12 | 294585 |
| 13 | 724869 |
| 14 | 1776717 |
| 15 | 4341425 |
| 16 | 10582177 |
| 17 | 25743269 |
| 18 | 62527553 |
| 19 | 151682821 |
| 20 | 367594457 |
| 21 | 890137893 |
| 22 | 2154129717 |
| 23 | 5210373929 |
| 24 | 12597758737 |
| 25 | 30449544885 |
| 26 | 73580024633 |
| 27 | 177767884973 |
| 28 | 429416696185 |
| 29 | 1037172672005 |
| 30 | 2504846014621 |