A033986 Order of first letter of n-th month of the year.
10, 6, 13, 1, 13, 10, 10, 1, 19, 15, 14, 4
Offset: 1
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.