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 | 141 |
| 3 | 521 |
| 4 | 1401 |
| 5 | 3101 |
| 6 | 6021 |
| 7 | 10641 |
| 8 | 17521 |
| 9 | 27301 |
| 10 | 40701 |
| 11 | 58521 |
| 12 | 81641 |
| 13 | 111021 |
| 14 | 147701 |
| 15 | 192801 |
| 16 | 247521 |
| 17 | 313141 |
| 18 | 391021 |
| 19 | 482601 |
| 20 | 589401 |
| 21 | 713021 |
| 22 | 855141 |
| 23 | 1017521 |
| 24 | 1202001 |
| 25 | 1410501 |
| 26 | 1645021 |
| 27 | 1907641 |
| 28 | 2200521 |
| 29 | 2525901 |
| 30 | 2886101 |
| 31 | 3283521 |