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 | 5 |
| 3 | 35 |
| 4 | 305 |
| 5 | 3125 |
| 6 | 36479 |
| 7 | 475295 |
| 8 | 6811205 |
| 9 | 106170245 |
| 10 | 1784531879 |
| 11 | 32117927231 |
| 12 | 615413731205 |
| 13 | 12493421510405 |
| 14 | 267608512061159 |
| 15 | 6026688403933967 |
| 16 | 142256385130774229 |
| 17 | 3509899012049396645 |
| 18 | 90301862963332188839 |
| 19 | 2417349828110572405823 |
| 20 | 67201548131159391828677 |