cp's OEIS Frontend

A319991 a(n) = Product_{d|n, d A019565(d)^[1 == d mod 3].

%I A319991 #9 Oct 03 2018 21:36:18
%S A319991 1,2,2,2,2,2,2,10,2,2,2,10,2,60,2,10,2,2,2,210,60,2,2,10,2,140,2,300,
%T A319991 2,42,2,110,2,2,60,10,2,132,140,210,2,60,2,1650,2,2,2,110,60,6468,2,
%U A319991 700,2,2,2,115500,132,2,2,210,2,4620,60,110,140,330,2,390,2,1260,2,10,2,260,308,660,60,140,2,210210,2,2,2,115500,2,1092,2
%N A319991 a(n) = Product_{d|n, d<n} A019565(d)^[1 == d mod 3].
%H A319991 Antti Karttunen, <a href="/A319991/b319991.txt">Table of n, a(n) for n = 1..8192</a>
%F A319991 a(n) = Product_{d|n, d<n} A019565(d)^[1 == d mod 3].
%F A319991 a(n) = A293214(n) / (A319990(n)*A319992(n)).
%F A319991 For all n >= 1:
%F A319991 A007814(a(n)) = A320001(n).
%F A319991 A048675(a(n)) = A293897(n).
%F A319991 A195017(a(n)) = A293895(n) mod 3.
%o A319991 (PARI)
%o A319991 A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ This function from _M. F. Hasler_
%o A319991 A319991(n) = { my(m=1); fordiv(n,d,if((d<n)&&(1==(d%3)),m *= A019565(d))); m; };
%Y A319991 Cf. A019565, A293214, A293895, A293897, A319990, A319992, A320001, A320011 (rgs-transform).
%Y A319991 Cf. also A293221.
%K A319991 nonn
%O A319991 1,2
%A A319991 _Antti Karttunen_, Oct 03 2018