OFFSET
1,1
COMMENTS
Sum of the geometric progression of ratio 2^n.
Number of all partial binary matrices with rows of length n: A partial binary matrix has 1<=k<=n rows of length n. The number of different partial matrices with k rows is 2^(k*n). a(n) is the sum for k between 1 and n.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..50
FORMULA
a(n) = Sum_{k=1..n} 2^(k*n).
MATHEMATICA
Table[(2^(n^2) - 1)/(1 - 1/2^n), {n, 1, 10}]
PROG
(PARI) a(n) = {(2^(n^2) - 1)/(1 - 1/2^n)} \\ Andrew Howroyd, Apr 26 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Olivier Gérard, Aug 08 2016
EXTENSIONS
Terms a(11) and beyond from Andrew Howroyd, Apr 26 2020
STATUS
approved