a(n) = (n+1)*(n+2)/2 * (2^n + 1)^n.A326012a(n) = (n+1)*(n+2)/2 * (2^n + 1)^n.Terms a(0) =1a(1) =9a(2) =150a(3) =7290a(4) =1252815a(5) =821843253External referencesoeis: A326012