Number of inequivalent (mod D_3) ways to place 4 points on a triangular grid of side n so that they are not vertices of an equilateral triangle with sides parallel to the grid.
A243209
Number of inequivalent (mod D_3) ways to place 4 points on a triangular grid of side n so that they are not vertices of an equilateral triangle with sides parallel to the grid.
Terms
- a(0) =1a(1) =25a(2) =186a(3) =881a(4) =3146a(5) =9264a(6) =23810a(7) =55058a(8) =117205a(9) =233135a(10) =438544a(11) =786541a(12) =1354696a(13) =2252202a(14) =3630684a(15) =5694984a(16) =8718963a(17) =13060515a(18) =19184110a(19) =27681103a(20) =39300096a(21) =54974216a(22) =75861038a(23) =103377456a(24) =139251749a(25) =185567453a(26) =244828780a(27) =320015885a(28) =414665890a(29) =532940080
External references
- oeis: A243209