A103824 - OEIS

A103824

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

%I #3 Mar 30 2012 17:29:22

%S 1,3,9,2,4,5,35,7,65,11,15,13,21,17,25,19,55,23,49,29,91,31,27,37,115,

%T 41,77,43,121,47,85,53,125,59,39,61,33,67,133,71,143,73,119,79,95,83,

%U 81,89,145,97,51,101,99,103,45,107,57,109,87,113,69,127,75,131,111,137

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

%Y Cf. A075593, A075594, A103825.

%K nonn

%O 1,2

%A _Ray Chandler_ Feb 16 2005

%E Definition corrected by Zak Seidov, Feb 20 2005