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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 3 |
| 7 | 6 |
| 8 | 12 |
| 9 | 25 |
| 10 | 54 |
| 11 | 120 |
| 12 | 278 |
| 13 | 657 |
| 14 | 1586 |
| 15 | 3885 |
| 16 | 9676 |
| 17 | 24350 |
| 18 | 61974 |
| 19 | 159066 |
| 20 | 411637 |
| 21 | 1072477 |
| 22 | 2812147 |
| 23 | 7414611 |
| 24 | 19650656 |
| 25 | 52319946 |
| 26 | 139898593 |
| 27 | 375536661 |
| 28 | 1011726481 |
| 29 | 2734793731 |
| 30 | 7415449225 |
| 31 | 20165442393 |
| 32 | 54986240994 |
| 33 | 150314506170 |
| 34 | 411889913114 |
| 35 | 1131183374539 |
| 36 | 3113153283443 |
| 37 | 8584839296108 |
| 38 | 23718157486109 |
| 39 | 65645273392938 |
| 40 | 181995130879151 |
| 41 | 505374042479921 |
| 42 | 1405493247220915 |
| 43 | 3914493122094481 |
| 44 | 10917513971606377 |
| 45 | 30489195524251154 |
| 46 | 85254349619909519 |
| 47 | 238677545463592954 |
| 48 | 668973050139380099 |
| 49 | 1877097093098685409 |
| 50 | 5272616851780131627 |