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 | 25 |
| 4 | 188 |
| 5 | 1671 |
| 6 | 17190 |
| 7 | 201125 |
| 8 | 2638984 |
| 9 | 38390179 |
| 10 | 613363466 |
| 11 | 10678267425 |
| 12 | 201215691660 |
| 13 | 4080450217247 |
| 14 | 88609322165902 |
| 15 | 2051573162708125 |
| 16 | 50450534991347216 |
| 17 | 1313219083705400475 |
| 18 | 36072797094375866898 |
| 19 | 1042811362801447763225 |
| 20 | 31647646914322017237652 |
| 21 | 1006032342980535954429463 |