Completely multiplicative with a(p) = p * a(p-1) for any prime number p.

Terms

a(0) =1a(1) =2a(2) =6a(3) =4a(4) =20a(5) =12a(6) =84a(7) =8a(8) =36a(9) =40a(10) =440a(11) =24a(12) =312a(13) =168a(14) =120a(15) =16a(16) =272a(17) =72a(18) =1368a(19) =80a(20) =504a(21) =880a(22) =20240a(23) =48a(24) =400a(25) =624a(26) =216a(27) =336a(28) =9744a(29) =240