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A140213 Product_{h|n and h mod 6 = 1} h; product of divisors of n of the form 6*k + 1.

%I A140213 #24 Jul 10 2017 06:02:22
%S A140213 1,1,1,1,1,1,7,1,1,1,1,1,13,7,1,1,1,1,19,1,7,1,1,1,25,13,1,7,1,1,31,1,
%T A140213 1,1,7,1,37,19,13,1,1,7,43,1,1,1,1,1,343,25,1,13,1,1,55,7,19,1,1,1,61,
%U A140213 31,7,1,13,1,67,1,1,7,1,1,73,37,25,19,7,13,79,1,1,1,1,7,85,43,1,1,1,1,8281
%N A140213 Product_{h|n and h mod 6 = 1} h; product of divisors of n of the form 6*k + 1.
%H A140213 Antti Karttunen, <a href="/A140213/b140213.txt">Table of n, a(n) for n = 1..10001</a>
%p A140213 A140213 := proc(n)
%p A140213     a := 1;
%p A140213     for d in numtheory[divisors](n) do
%p A140213         if modp(d,6) = 1 then
%p A140213             a := a*d ;
%p A140213         end if;
%p A140213     end do:
%p A140213     a;
%p A140213 end proc: # _R. J. Mathar_, Dec 15 2015
%o A140213 (PARI) A140213(n) = { my(m=1); fordiv(n, d, if(1==(d%6), m *= d)); (m); }; \\ _Antti Karttunen_, Jul 09 2017
%Y A140213 Cf. A170824, A248909, A279060.
%K A140213 nonn,easy,look
%O A140213 1,7
%A A140213 _R. J. Mathar_, Jun 27 2008
%E A140213 More terms from _D. S. McNeil_, Mar 24 2009