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 | 3 |
| 3 | 7 |
| 4 | 18 |
| 5 | 49 |
| 6 | 142 |
| 7 | 438 |
| 8 | 1405 |
| 9 | 4630 |
| 10 | 15595 |
| 11 | 53493 |
| 12 | 186112 |
| 13 | 655421 |
| 14 | 2331057 |
| 15 | 8362451 |
| 16 | 30222369 |
| 17 | 109930284 |
| 18 | 402134685 |
| 19 | 1478480102 |
| 20 | 5460253675 |
| 21 | 20247271086 |
| 22 | 75353895375 |
| 23 | 281374686795 |
| 24 | 1053846512655 |
| 25 | 3957966801068 |
| 26 | 14902939174394 |
| 27 | 56245902561309 |
| 28 | 212741751056939 |