cp's OEIS Frontend

A175210 a(n) = largest prime (or 1, if no such prime exists) that is < p(n) and whose binary representation occurs as a substring in the binary representation of p(n), where p(n) is the n-th prime.

%I A175210 #8 Mar 11 2014 01:32:51
%S A175210 1,1,2,3,5,5,2,3,11,13,7,5,5,11,23,13,29,29,3,17,2,19,41,11,3,37,19,
%T A175210 53,13,17,31,3,17,17,37,37,29,17,83,43,89,53,47,3,17,71,83,47,113,101,
%U A175210 41,59,113,61,2,131,67,67,17,17,17,73,19,23,19,79,41,17,173,43,97,179,47
%N A175210 a(n) = largest prime (or 1, if no such prime exists) that is < p(n) and whose binary representation occurs as a substring in the binary representation of p(n), where p(n) is the n-th prime.
%C A175210 Only a(1) and a(2) = 1.
%e A175210 29, the 10th prime, is 11101 in binary. The largest prime that is < 29 and whose binary representation occurs as a substring in this is 13 (1101 in binary), which occurs in binary 29 as follows: 1(1101). So a(10) = 13.
%K A175210 base,nonn
%O A175210 1,3
%A A175210 _Leroy Quet_, Mar 05 2010
%E A175210 Extended by _Ray Chandler_, Mar 13 2010