%I A109738
%S A109738 1,2,1,5,2,13,26,43,62,85,114,145,182,223,266,313,366,425,486,553,624,
%T A109738 697,776,859,948,1045,1146,1249,1356,1465,1578,1705,1836,1973,2112,2261,
%U A109738 2412,2569,2732,2899,3072,3251,3432,3623,3816,4013,4212,4423,4646,4873
%V A109738 1,2,-1,-5,2,13,26,43,62,85,114,145,182,223,266,313,366,425,486,553,624,
               697,776,859,
%W A109738 948,1045,1146,1249,1356,1465,1578,1705,1836,1973,2112,2261,2412,2569,
               2732,2899,3072,
%X A109738 3251,3432,3623,3816,4013,4212,4423,4646,4873
%N A109738 a(0)=1; for n>0, a(n) = a(n-1) S prime(n), where S is + if n is odd and 
               a(n-1) is even, x if n is odd and a(n-1) is odd, - if n is even and 
               a(n-1) is even, + if n is even and a(n-1) is odd.
%t A109738 f[l_] := Append[l, Apply[{Subtract, Plus, Plus, Times}[[2*Mod[Length[l], 
               2] + Mod[Last[l], 2] + 1]], {Last[l], Prime[Length[l]]}]]; Nest[f, 
               {1}, 50] (*Chandler*)
%Y A109738 A corrected version of A109623.
%Y A109738 Sequence in context: A109191 A087123 A097131 this_sequence A143891 A030400 
               A115345
%Y A109738 Adjacent sequences: A109735 A109736 A109737 this_sequence A109739 A109740 
               A109741
%K A109738 sign
%O A109738 0,2
%A A109738 N. J. A. Sloane (njas(AT)research.att.com), following a communication 
               from Harry Yang (yexing_yang(AT)msn.com), Aug 11 2005
%E A109738 Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. 
               Wilson v, Aug 12 2005