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A123491 Diagonal sums of number triangle A123490. 2
1, 2, 5, 10, 22, 48, 112, 274, 715, 1982, 5837, 18180, 59644, 205296, 739032, 2775180, 10846965, 44039754, 185391469, 807776198, 3637193474, 16900721824, 80939650552, 399061251246, 2023408865983, 10540656630118 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..675

FORMULA

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

MATHEMATICA

Table[Sum[((k + 2)^(n - 2 k) + k)/(k + 1), {k, 0, Floor[n/2]}], {n, 0, 50}] (* G. C. Greubel, Oct 14 2017 *)

PROG

(PARI) for(n=0, 25, print1(sum(k=0, floor(n/2), ((k + 2)^(n - 2 k) + k)/(k + 1)), ", ")) \\ G. C. Greubel, Oct 14 2017

CROSSREFS

Cf. A123490.

Sequence in context: A320650 A018109 A341020 * A329185 A232163 A166300

Adjacent sequences:  A123488 A123489 A123490 * A123492 A123493 A123494

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Oct 01 2006

STATUS

approved

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Last modified April 14 21:21 EDT 2021. Contains 342962 sequences. (Running on oeis4.)