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%I #3 Mar 30 2012 18:59:06
%S 1,1,2,3,5,8,14,26,53,117,280,721,1989,5844,18188,59652,205305,739041,
%T 2775190,10846975,44039765,185391480,807776210,3637193486,16900721837,
%U 80939650565,399061251260,2023408865997,10540656630133,56362743769012
%N Diagonal sums of a sum-of-powers triangle.
%C Diagonal sums of A104878.
%F a(0)=1, a(1)=1, a(n)=n+sum{k=2..floor(n/2), (k^(n-2k+1)-1)/(k-1)}, n>1.
%K easy,nonn
%O 0,3
%A _Paul Barry_, Mar 28 2005