Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 4 ones in any 3 X 3 X 3 subtriangle.
A153931
Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 4 ones in any 3 X 3 X 3 subtriangle.
Terms
- a(0) =1a(1) =2a(2) =2a(3) =3a(4) =5a(5) =9a(6) =17a(7) =59a(8) =104a(9) =345a(10) =1199a(11) =3851a(12) =12806a(13) =82134a(14) =263587a(15) =1652702a(16) =10527130a(17) =63679653a(18) =393522264a(19) =4714694321a(20) =28217205768a(21) =327320006475
External references
- oeis: A153931