%I A131093
%S A131093 1,2,3,7,18,29,69,178,287,683,1762,2841,6761,17442,28123,66927,172658,
%T A131093 278389,662509,1709138,2755767,6558163,16918722,27279281,64919121,
%U A131093 167478082,270037043,642633047,1657862098,2673091149
%N A131093 a(1)=1, a(n) = a(n-1) + sum of odd numbers which are among the first 
               (n-1) terms of the sequence.
%C A131093 a(n) mod 2 = A011655(n+1);
%C A131093 a(n) = a(n-1) + Sum(a(k)*(a(k) mod 2): 1<=k<n), a(1) = 1.
%H A131093 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               OddNumber.html">Odd Number</a>
%Y A131093 Cf. A096777, A101135.
%Y A131093 Sequence in context: A059801 A102226 A058334 this_sequence A002864 A005248 
               A032102
%Y A131093 Adjacent sequences: A131090 A131091 A131092 this_sequence A131094 A131095 
               A131096
%K A131093 nonn
%O A131093 1,2
%A A131093 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 14 2007