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 | 4 |
| 3 | 16 |
| 4 | 83 |
| 5 | 526 |
| 6 | 3826 |
| 7 | 31338 |
| 8 | 285556 |
| 9 | 2857831 |
| 10 | 31083421 |
| 11 | 364523891 |
| 12 | 4579906098 |
| 13 | 61313286380 |
| 14 | 870531542926 |
| 15 | 13055593578453 |
| 16 | 206097824225131 |
| 17 | 3414146518958089 |
| 18 | 59189048364709453 |
| 19 | 1071264611091540458 |
| 20 | 20197719805598878119 |
| 21 | 395917304689782855768 |