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a(n) = Product_{h == 5 (mod 6) and h|n} h.
5

%I #13 Jan 07 2021 01:17:53

%S 1,1,1,1,5,1,1,1,1,5,11,1,1,1,5,1,17,1,1,5,1,11,23,1,5,1,1,1,29,5,1,1,

%T 11,17,175,1,1,1,1,5,41,1,1,11,5,23,47,1,1,5,17,1,53,1,55,1,1,29,59,5,

%U 1,1,1,1,325,11,1,17,23,175,71,1,1,1,5,1,847,1,1,5,1,41,83,1,85,1,29,11

%N a(n) = Product_{h == 5 (mod 6) and h|n} h.

%C Not multiplicative: a(5)*a(7) <> a(35). - _R. J. Mathar_, Oct 08 2011

%p A140214 := proc(n) a := 1 ; for h in numtheory[divisors](n) do if (h mod 6) = 5 then a := a*h: fi; od: a; end:

%p seq(A140214(n),n=1..120) ; # _R. J. Mathar_, Jun 24 2009

%K nonn,easy

%O 1,5

%A _R. J. Mathar_, Jun 27 2008