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 A081972 Consider the geometric progression 1,1/2,1/4,1/8,1/16,1/32,1/64,... Group the terms such that the n-th group contains n terms like this (1/1),(1/2,1/4),(1/8,1/16,1,32),(1/64,1/128,1/256,1/512),... a(n) = floor[1/s(n)] where s(n) is the sum of the members of the n-th group. 0

%I

%S 1,1,4,34,528,16644,1056832,134744072,34426978560,17609382707216,

%T 18023198899569664,36902497546234101792,151134176447977081540608,

%U 1238015601761073699807559744,20283028592561355523908308058112

%N Consider the geometric progression 1,1/2,1/4,1/8,1/16,1/32,1/64,... Group the terms such that the n-th group contains n terms like this (1/1),(1/2,1/4),(1/8,1/16,1,32),(1/64,1/128,1/256,1/512),... a(n) = floor[1/s(n)] where s(n) is the sum of the members of the n-th group.

%F a(n) = floor((2^(n*(n+1)/2 - 1))/(2^n-1)).

%K nonn

%O 1,3

%A _Amarnath Murthy_, Apr 03 2003

%E Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003

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Last modified January 27 09:20 EST 2022. Contains 350607 sequences. (Running on oeis4.)