A380806 Numbers not of form a*(b+1) + b*(c+1) + c*(a+1) for 1<=a<=b<=c.
1, 2, 3, 4, 5, 7, 8, 10, 11, 14, 16, 19, 20, 26, 31, 34, 40, 44, 55, 76, 80, 94, 124, 160, 170, 220, 271
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.