Number of convex quadrilaterals, distinct up to congruence, on an n X n grid (or geoboard).

Terms

a(0) =0a(1) =1a(2) =12a(3) =89a(4) =407a(5) =1413a(6) =3894a(7) =9431a(8) =20212a(9) =39847a(10) =73177a(11) =127582a(12) =211012a(13) =337186a(14) =519594a(15) =777447a(16) =1134269a(17) =1620415a(18) =2264873a(19) =3114709a(20) =4209184a(21) =5609209a(22) =7378581a(23) =9594611a(24) =12326333a(25) =15688198a(26) =19779188a(27) =24721601a(28) =30646522a(29) =37727553