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 | 20 |
| 2 | 220 |
| 3 | 2330 |
| 4 | 24640 |
| 5 | 261050 |
| 6 | 2771560 |
| 7 | 29487170 |
| 8 | 314358880 |
| 9 | 3357947690 |
| 10 | 35937424600 |
| 11 | 385311670610 |
| 12 | 4138428376720 |
| 13 | 44522712143930 |
| 14 | 479749833583240 |
| 15 | 5177248169415650 |
| 16 | 55949729863572160 |
| 17 | 605447028499293770 |