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 | 12 |
| 4 | 37 |
| 5 | 118 |
| 6 | 387 |
| 7 | 1298 |
| 8 | 4433 |
| 9 | 15366 |
| 10 | 53924 |
| 11 | 191216 |
| 12 | 684114 |
| 13 | 2466428 |
| 14 | 8951945 |
| 15 | 32683230 |
| 16 | 119949945 |
| 17 | 442281030 |
| 18 | 1637618400 |
| 19 | 6086481720 |
| 20 | 22699003830 |
| 21 | 84918443220 |
| 22 | 318593346630 |
| 23 | 1198421583684 |
| 24 | 4518886787802 |
| 25 | 17077448924828 |
| 26 | 64671604514552 |
| 27 | 245380598678208 |
| 28 | 932708665735364 |
| 29 | 3551238550341944 |
| 30 | 13542393822575541 |