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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 22 |
| 4 | 154 |
| 5 | 1306 |
| 6 | 12994 |
| 7 | 148282 |
| 8 | 1908274 |
| 9 | 27333706 |
| 10 | 431220034 |
| 11 | 7428550042 |
| 12 | 138737478994 |
| 13 | 2792050329706 |
| 14 | 60231133487074 |
| 15 | 1386484468239802 |
| 16 | 33921605427779314 |
| 17 | 878976357571495306 |
| 18 | 24046780495646314114 |
| 19 | 692622345890928153562 |
| 20 | 20950628198687114521234 |
| 21 | 663992311200423614606506 |