Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 2.
A166197
Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 2.
Terms
- a(0) =1a(1) =3a(2) =1a(3) =2a(4) =6a(5) =12a(6) =26a(7) =90a(8) =200a(9) =665a(10) =3980a(11) =10515a(12) =52518a(13) =433447a(14) =1973317a(15) =14252749a(16) =166762668a(17) =1065468116a(18) =11148385916a(19) =193707228525
External references
- oeis: A166197