Replace all prime factors p of n with n-p.

Terms

a(0) =1a(1) =0a(2) =0a(3) =4a(4) =0a(5) =12a(6) =0a(7) =216a(8) =36a(9) =40a(10) =0a(11) =900a(12) =0a(13) =84a(14) =120a(15) =38416a(16) =0a(17) =3600a(18) =0a(19) =4860a(20) =252a(21) =220a(22) =0a(23) =223608a(24) =400a(25) =312a(26) =13824a(27) =14196a(28) =0a(29) =18900