cp's OEIS Frontend

A103666 Primes p such that the largest prime divisor of p-1 is less than the largest prime divisor of p+1.

%I A103666 #7 Nov 21 2013 12:48:38
%S A103666 5,13,17,19,37,41,43,61,67,73,97,101,109,113,137,151,157,163,181,193,
%T A103666 197,211,229,241,251,257,271,277,281,283,313,331,337,353,379,397,401,
%U A103666 409,421,433,443,457,463,487,491,521,523,541,547,577,601,613,617,631
%N A103666 Primes p such that the largest prime divisor of p-1 is less than the largest prime divisor of p+1.
%H A103666 Karl Hovekamp, <a href="/A103666/b103666.txt">Table of n, a(n) for n=1..39168</a>
%e A103666 a(1)=5 because the largest prime divisor of 4 is less than the largest prime divisor of 6.
%t A103666 Select[Prime[Range[2,200]],Max[Transpose[FactorInteger[#-1]][[1]]]< Max[Transpose[FactorInteger[#+1]][[1]]]&]  (* _Harvey P. Dale_, Apr 26 2011 *)
%Y A103666 Cf. A023503 greatest prime divisor of n-th prime - 1, A023509 greatest prime divisor of n-th prime + 1, A103667.
%K A103666 nonn
%O A103666 1,1
%A A103666 _Hugo Pfoertner_, Feb 19 2005