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 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | -2 |
| 5 | -4 |
| 6 | -10 |
| 7 | -25 |
| 8 | -66 |
| 9 | -178 |
| 10 | -490 |
| 11 | -1370 |
| 12 | -3881 |
| 13 | -11113 |
| 14 | -32115 |
| 15 | -93542 |
| 16 | -274332 |
| 17 | -809377 |
| 18 | -2400641 |
| 19 | -7154066 |
| 20 | -21409915 |
| 21 | -64317898 |
| 22 | -193886665 |
| 23 | -586311736 |
| 24 | -1778101466 |
| 25 | -5406660260 |
| 26 | -16479943037 |
| 27 | -50344990445 |
| 28 | -154120149335 |
| 29 | -472717222756 |
| 30 | -1452529814867 |
| 31 | -4470733286364 |
| 32 | -13782117172530 |
| 33 | -42549485082664 |
| 34 | -131545321942331 |