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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 46 |
| 5 | 154 |
| 6 | 533 |
| 7 | 1802 |
| 8 | 6137 |
| 9 | 20729 |
| 10 | 69971 |
| 11 | 235193 |
| 12 | 789000 |
| 13 | 2639004 |
| 14 | 8807811 |
| 15 | 29327841 |
| 16 | 97456878 |
| 17 | 323206002 |
| 18 | 1069923013 |
| 19 | 3535612108 |
| 20 | 11664423298 |
| 21 | 38422208659 |
| 22 | 126374059558 |
| 23 | 415069188175 |
| 24 | 1361443135562 |
| 25 | 4459861400156 |
| 26 | 14591869576268 |
| 27 | 47686017637926 |