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 | 21 |
| 2 | 110 |
| 3 | 4599 |
| 4 | 11990 |
| 5 | 249501 |
| 6 | 1295030 |
| 7 | 107308383 |
| 8 | 138627830 |
| 9 | 2859244731 |
| 10 | 14712346550 |
| 11 | 604396290309 |
| 12 | 1548795089270 |
| 13 | 31691625960561 |
| 14 | 161831110601270 |
| 15 | 26399564969194431 |
| 16 | 16795789262584310 |
| 17 | 341432673486734991 |
| 18 | 1732778326412587190 |
| 19 | 70259641081276811619 |