a(n) is number of permutations (p(1),p(2),p(3),...,p(n)) of (1,2,3,...,n) such that p(k) is coprime to p(n+1-k) for k = all positive integers <= n.

A133922

a(n) is number of permutations (p(1),p(2),p(3),...,p(n)) of (1,2,3,...,n) such that p(k) is coprime to p(n+1-k) for k = all positive integers <= n.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =16a(4) =16a(5) =192a(6) =192a(7) =6912a(8) =4608a(9) =230400a(10) =230400a(11) =11612160a(12) =11612160a(13) =1199923200a(14) =588349440a(15) =98594979840a(16) =98594979840

External references