Numbers k such that k = Product (p_j^e_j) = Product (pi(p_j)*p_j), where pi() = A000720.

Terms

a(0) =1a(1) =2a(2) =12a(3) =56a(4) =180a(5) =304a(6) =336a(7) =936a(8) =1696a(9) =1824a(10) =2484a(11) =5040a(12) =5328a(13) =6664a(14) =8384a(15) =8512a(16) =9900a(17) =10176a(18) =13176a(19) =14040a(20) =25632a(21) =26208a(22) =27360a(23) =33372a(24) =33712a(25) =37260a(26) =39808a(27) =39984a(28) =47488a(29) =50304