cp's OEIS Frontend

A225716 Composite squarefree numbers n such that p(i)+6 divides n-6, where p(i) are the prime factors of n.

%I A225716 #11 Nov 15 2013 05:27:10
%S A225716 6,26781,120791,5099531,5720435,14637451,24110358,31552261,33792198,
%T A225716 57804181,71925054,88324781,92849126,441031331,650715071,924029951,
%U A225716 1425902869,2093676486,2336689491,3273172441,4533042611,4711366831,5162021871,5502040431,6427899582
%N A225716 Composite squarefree numbers n such that p(i)+6 divides n-6, where p(i) are the prime factors of n.
%e A225716 Prime factors of 14637451 are 41, 229 and 1559. We have that (14637451-6)/(41+6) = 311435, (14637451-6)/(229+6) = 62287 and (14637451-6)/(1559+6) = 9353.
%p A225716 with(numtheory); A225716:=proc(i,j) local c, d, n, ok, p, t;
%p A225716 for n from 2 to i do if not isprime(n) then p:=ifactors(n)[2]; ok:=1;
%p A225716 for d from 1 to nops(p) do if p[d][2]>1 or p[d][1]=j then ok:=0; break; fi;
%p A225716 if  not type((n+j)/(p[d][1]-j),integer) then ok:=0; break; fi; od;
%p A225716 if ok=1 then print(n); fi; fi; od; end: A225716(10^9,-6);
%Y A225716 Cf. A208728, A225702-A225715, A225717-A225720.
%K A225716 nonn
%O A225716 1,1
%A A225716 _Paolo P. Lava_, May 13 2013
%E A225716 a(14)-a(25) from _Donovan Johnson_, Nov 15 2013