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 | 7 |
| 1 | 39 |
| 2 | 199 |
| 3 | 999 |
| 4 | 4999 |
| 5 | 24999 |
| 6 | 124999 |
| 7 | 624999 |
| 8 | 3124999 |
| 9 | 15624999 |
| 10 | 78124999 |
| 11 | 390624999 |
| 12 | 1953124999 |
| 13 | 9765624999 |
| 14 | 48828124999 |
| 15 | 244140624999 |
| 16 | 1220703124999 |
| 17 | 6103515624999 |
| 18 | 30517578124999 |
| 19 | 152587890624999 |
| 20 | 762939453124999 |