Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle of any orientation.
A243142
Number of inequivalent (mod D_3) ways to place 3 points on a triangular grid of side n so that they are not vertices of an equilateral triangle of any orientation.
Terms
- a(0) =0a(1) =3a(2) =19a(3) =75a(4) =218a(5) =542a(6) =1178a(7) =2350a(8) =4340a(9) =7585a(10) =12605a(11) =20153a(12) =31094a(13) =46620a(14) =68068a(15) =97212a(16) =136008a(17) =186975a(18) =252855a(19) =337095a(20) =443410a(21) =576378a(22) =740894a(23) =942890a(24) =1188668a(25) =1485757a(26) =1842113a(27) =2267125a(28) =2770670a(29) =3364280
External references
- oeis: A243142