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Product of first n odd nonprimes, a(n) = Product_{k=1..n} A071904(k).
0

%I #55 Dec 10 2023 18:07:45

%S 1,9,135,2835,70875,1913625,63149625,2210236875,86199238125,

%T 3878965715625,190069320065625,9693535323346875,533144442784078125,

%U 30389233238692453125,1914521694037624546875,124443910112445595546875,8586629797758746092734375

%N Product of first n odd nonprimes, a(n) = Product_{k=1..n} A071904(k).

%t With[{nn = 70}, FoldList[Times, Complement[Range[1, nn, 2], Prime@ Range[2, PrimePi@ nn]]]] (* _Michael De Vlieger_, Apr 21 2019 *)

%o (PARI) lista(nn) = {my(p=1); print1(p, ", "); forcomposite (n=1, nn, if (n%2, p *= n; print1(p, ", ")); ); } \\ _Michel Marcus_, Mar 13 2019

%Y Cf. A071904, A036691, A002866, A001147.

%K nonn

%O 0,2

%A _Zhandos Mambetaliyev_, Mar 13 2019