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 | 3 |
| 3 | 19 |
| 4 | 161 |
| 5 | 1781 |
| 6 | 24667 |
| 7 | 409991 |
| 8 | 7959233 |
| 9 | 176920489 |
| 10 | 4432942931 |
| 11 | 123648692795 |
| 12 | 3800647961761 |
| 13 | 127654261471517 |
| 14 | 4651982506605995 |
| 15 | 182824074836850991 |
| 16 | 7708128977570816129 |
| 17 | 347059689259637711441 |
| 18 | 16621016953663100702755 |
| 19 | 843658152872351669816675 |