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 | -1 |
| 2 | -1 |
| 3 | -3 |
| 4 | -6 |
| 5 | -14 |
| 6 | -31 |
| 7 | -70 |
| 8 | -157 |
| 9 | -353 |
| 10 | -793 |
| 11 | -1782 |
| 12 | -4004 |
| 13 | -8997 |
| 14 | -20216 |
| 15 | -45425 |
| 16 | -102069 |
| 17 | -229347 |
| 18 | -515338 |
| 19 | -1157954 |
| 20 | -2601899 |
| 21 | -5846414 |
| 22 | -13136773 |
| 23 | -29518061 |
| 24 | -66326481 |
| 25 | -149034250 |
| 26 | -334876920 |
| 27 | -752461609 |
| 28 | -1690765888 |
| 29 | -3799116465 |
| 30 | -8536537209 |