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 | 11 |
| 2 | 49 |
| 3 | 225 |
| 4 | 1043 |
| 5 | 4861 |
| 6 | 22723 |
| 7 | 106401 |
| 8 | 498703 |
| 9 | 2338691 |
| 10 | 10970731 |
| 11 | 51472161 |
| 12 | 241518759 |
| 13 | 1133320429 |
| 14 | 5318237121 |
| 15 | 24956866179 |
| 16 | 117116084385 |
| 17 | 549598276829 |
| 18 | 2579143380799 |
| 19 | 12103370927679 |
| 20 | 56798597444915 |
| 21 | 266544122924215 |