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%I #16 Jun 22 2020 04:49:39
%S 25,35,49,55,65,77,85,91,95,115,125,133,155,161,169,175,209,221,235,
%T 253,259,265,275,295,305,319,329,335,355,361,365,371,377,385,391,395,
%U 403,407,437,445,451,455,469,481,485,493,497,505,511,539,545,559,565,575
%N Composite numbers in sequence A107323.
%H Robert Israel, <a href="/A107472/b107472.txt">Table of n, a(n) for n = 1..10000</a>
%p a:=proc(n) if ithprime(n) mod 6 = 5 then ithprime(n)+2 elif ithprime(n) mod 6 = 1 then ithprime(n)-2 else 0 fi end: A:=[seq(a(n),n=3..130)]: b:=proc(n) if isprime(A[n])=false then A[n] else fi end: seq(b(m),m=1..nops(A)); # _Emeric Deutsch_, Jun 19 2005
%t f[p_] := If[Mod[p, 6] == 5, p + 2, p - 2];
%t Select[f /@ Prime[Range[3, 200]], CompositeQ] (* _Jean-François Alcover_, Jun 22 2020 *)
%K nonn
%O 1,1
%A _Leroy Quet_, May 27 2005
%E More terms from _Emeric Deutsch_, Jun 19 2005
%E Offset corrected by _Robert Israel_, Apr 02 2018
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