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A104880 Diagonal sums of a sum-of-powers triangle. 1
1, 1, 2, 3, 5, 8, 14, 26, 53, 117, 280, 721, 1989, 5844, 18188, 59652, 205305, 739041, 2775190, 10846975, 44039765, 185391480, 807776210, 3637193486, 16900721837, 80939650565, 399061251260, 2023408865997, 10540656630133, 56362743769012 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Diagonal sums of A104878.

LINKS

Table of n, a(n) for n=0..29.

FORMULA

a(0)=1, a(1)=1, a(n)=n+sum{k=2..floor(n/2), (k^(n-2k+1)-1)/(k-1)}, n>1.

CROSSREFS

Sequence in context: A212657 A065955 A196118 * A152478 A102973 A066372

Adjacent sequences:  A104877 A104878 A104879 * A104881 A104882 A104883

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Mar 28 2005

STATUS

approved

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Last modified March 20 15:43 EDT 2019. Contains 321345 sequences. (Running on oeis4.)