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a(n) = Sum_{k=1..n} C(n,k) mod k.
3

%I #10 Jan 31 2017 03:04:48

%S 0,1,2,2,3,8,9,11,6,13,14,26,27,28,32,46,47,49,50,68,81,82,83,116,102,

%T 101,105,105,106,142,143,143,153,172,165,222,223,216,259,278,279,256,

%U 257,327,394,295,296,422,374,318,328,384,385,420,469,461,465,450,451

%N a(n) = Sum_{k=1..n} C(n,k) mod k.

%H Paolo P. Lava, <a href="/A076541/b076541.txt">Table of n, a(n) for n = 1..2500</a>

%F a(n) seems to be asymptotic to c*n^2 with c around 0.18...

%o (PARI) a(n)=sum(k=1,n,binomial(n,k)%k)

%Y Row sums of A081371.

%K nonn

%O 1,3

%A _Benoit Cloitre_, Oct 19 2002