A103935 - cp's OEIS frontend

A103935 Choose a(n) to be the smallest odd number not yet used such that: a(1) = 1, a(2n) = composite, a(2n+1) = prime and partial sums are alternately composite or prime.

%I A103935 #5 Jul 09 2025 04:24:45
%S A103935 1,9,3,15,13,21,5,25,11,27,7,33,23,35,29,39,17,45,31,49,19,51,61,55,
%T A103935 37,57,43,63,53,65,41,69,71,75,79,77,73,81,59,85,47,87,103,91,83,93,
%U A103935 113,95,109,99,127,105,149,111,139,115,89,117,107,119,97,121,131,123,67,125
%N A103935 Choose a(n) to be the smallest odd number not yet used such that: a(1) = 1, a(2n) = composite, a(2n+1) = prime and partial sums are alternately composite or prime.
%Y A103935 Cf. A075593, A075594, A103824, A103825, A103934.
%K A103935 nonn
%O A103935 1,2
%A A103935 _Ray Chandler_ Feb 21 2005, based on a suggestion from Zak Seidov

cp's OEIS Frontend

A103935 Choose a(n) to be the smallest odd number not yet used such that: a(1) = 1, a(2n) = composite, a(2n+1) = prime and partial sums are alternately composite or prime.