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A026960 a(n) = Sum_{k=0..n} (k+1) * A026615(n,k). 1
1, 3, 10, 30, 78, 189, 440, 999, 2230, 4917, 10740, 23283, 50162, 107505, 229360, 487407, 1032174, 2179053, 4587500, 9633771, 20185066, 42205161, 88080360, 183500775, 381681638, 792723429, 1644167140, 3405774819, 7046430690, 14562623457, 30064771040 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (6,-13,12,-4).

FORMULA

For n>1, a(n) = 7*(n+2)*2^(n-3) - n - 2.

From Colin Barker, Feb 18 2016: (Start)

a(n) = 6*a(n-1)-13*a(n-2)+12*a(n-3)-4*a(n-4) for n>5

G.f.: (1-3*x+5*x^2-3*x^3-4*x^4+3*x^5) / ((1-x)^2*(1-2*x)^2).

(End)

MATHEMATICA

Join[{1, 3}, Table[7(n+2)2^(n-3)-n-2, {n, 2, 30}]] (* or *) LinearRecurrence[ {6, -13, 12, -4}, {1, 3, 10, 30, 78, 189}, 30] (* Harvey P. Dale, Oct 31 2015 *)

PROG

(PARI) Vec((1-3*x+5*x^2-3*x^3-4*x^4+3*x^5)/((1-x)^2*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 18 2016

CROSSREFS

Sequence in context: A166174 A006484 A144007 * A026990 A254822 A027256

Adjacent sequences:  A026957 A026958 A026959 * A026961 A026962 A026963

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)