S(n; 1,0) = S(n; 3,0) 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.

A068786

S(n; 1,0) = S(n; 3,0) 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) =1a(1) =2a(2) =6a(3) =16a(4) =40a(5) =192a(6) =896a(7) =4096a(8) =17536a(9) =69632a(10) =270336a(11) =1048576a(12) =4126720a(13) =16515072a(14) =66584576a(15) =268435456a(16) =1077968896a(17) =4311744512a(18) =17213423616a(19) =68719476736a(20) =274608947200

External references