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%I #8 Aug 31 2017 23:03:25
%S 1,3,6,13,27,54,109,218,437,874,1749,3499,6998,13997,27995,55991,
%T 111982,223965,447931,895862,1791725,3583450,7166901,14333802,
%U 28667605,57335211,114670422,229340845,458681691,917363382,1834726765,3669453531,7338907062,14677814125,29355628250,58711256501,117422513002,234845026005
%N a(n) is the length of stage n in A137843.
%F a(1) = 1; for n > 1, a(n) = 2*a(n-1) + (A137843(n-1) mod 2).
%o (Scheme) ;; Use the program given in A137843.
%Y Cf. A137843, A291754.
%Y a(n) differs from similar A112306(n-1) for the first time at n=15, where a(15) = 27995, while A112306(14) = 27994.
%K nonn
%O 1,2
%A _Antti Karttunen_, Aug 31 2017