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 | 5 |
| 2 | 19 |
| 3 | 65 |
| 4 | 247 |
| 5 | 955 |
| 6 | 3733 |
| 7 | 14649 |
| 8 | 57583 |
| 9 | 226505 |
| 10 | 891219 |
| 11 | 3507047 |
| 12 | 13801285 |
| 13 | 54313277 |
| 14 | 213745019 |
| 15 | 841177105 |
| 16 | 3310392415 |
| 17 | 13027820227 |
| 18 | 51270096661 |
| 19 | 201769982673 |
| 20 | 794052091767 |
| 21 | 3124938240153 |
| 22 | 12297982928987 |
| 23 | 48397879544975 |