Number of scalene triangles, distinct up to congruence, on a centered hexagonal grid of size n.

Terms

a(0) =0a(1) =1a(2) =19a(3) =99a(4) =310a(5) =760a(6) =1556a(7) =2863a(8) =4849a(9) =7713a(10) =11702a(11) =17077a(12) =24066a(13) =33021a(14) =44272a(15) =58180a(16) =75148a(17) =95526a(18) =119758a(19) =148489a(20) =181924a(21) =220796a(22) =265519a(23) =316736a(24) =375006a(25) =441061a(26) =515467a(27) =598680a(28) =691761a(29) =795410