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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
1, 1, 4, 34, 528, 16644, 1056832, 134744072, 34426978560, 17609382707216, 18023198899569664, 36902497546234101792, 151134176447977081540608, 1238015601761073699807559744, 20283028592561355523908308058112
OFFSET
1,3
FORMULA
a(n) = floor((2^(n*(n+1)/2 - 1))/(2^n-1)).
CROSSREFS
Sequence in context: A198908 A207864 A222077 * A158961 A134354 A333981
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 03 2003
EXTENSIONS
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003
STATUS
approved