6, 11, 16, 21, 26, 31, 36,...
3, 6, 9, 12, 15,...
5, 8, 11, 14, 17, 20,...
7, 11, 15, 19, 23, 27,...
2n+1
4c+1
4a+3
5d
2a
3b
5n+1
3n+2