a(n) = sqrt(floor(n/2)! * Product_{k=1..n} Product_{i=1..k-1} gcd(k,i)).

A224497

a(n) = sqrt(floor(n/2)! * Product_{k=1..n} Product_{i=1..k-1} gcd(k,i)).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =12a(7) =12a(8) =96a(9) =288a(10) =5760a(11) =5760a(12) =829440a(13) =829440a(14) =46448640a(15) =2090188800a(16) =267544166400a(17) =267544166400

External references