S(n; 0,1) = S(n; 2,3) where S(n; t,s) is the number of length n 4-ary strings whose digits sum to t mod 4 and whose sum of products of all pairs of digits sum to s mod 4.

A068711

S(n; 0,1) = S(n; 2,3) where S(n; t,s) is the number of length n 4-ary strings whose digits sum to t mod 4 and whose sum of products of all pairs of digits sum to s mod 4.

Terms

    a(0) =0a(1) =0a(2) =6a(3) =24a(4) =80a(5) =272a(6) =896a(7) =3584a(8) =15360a(9) =65280a(10) =270336a(11) =1081344a(12) =4259840a(13) =16781312a(14) =66584576a(15) =266338304a(16) =1069547520a(17) =4294901760a(18) =17213423616a(19) =68853694464a(20) =275146342400

External references