S(n; 1,1) = S(n; 3,1) 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.

A068778

S(n; 1,1) = S(n; 3,1) 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) =0a(3) =16a(4) =80a(5) =320a(6) =1184a(7) =4096a(8) =15360a(9) =61440a(10) =253440a(11) =1048576a(12) =4259840a(13) =17039360a(14) =67641344a(15) =268435456a(16) =1069547520a(17) =4278190080a(18) =17146183680a(19) =68719476736a(20) =275146342400

External references