a(n) = A107668(n)/(n+1)^2.A107669a(n) = A107668(n)/(n+1)^2.Terms a(0) =1a(1) =1a(2) =5a(3) =51a(4) =809a(5) =17575a(6) =486460a(7) =16384260a(8) =650574249a(9) =29762953831External referencesoeis: A107669