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A291526 a(n) = 2^n*(n - 3) + 4. 0
0, 0, 4, 20, 68, 196, 516, 1284, 3076, 7172, 16388, 36868, 81924, 180228, 393220, 851972, 1835012, 3932164, 8388612, 17825796, 37748740, 79691780, 167772164, 352321540, 738197508, 1543503876, 3221225476, 6710886404, 13958643716, 28991029252, 60129542148 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Also the skewness of the (n+1)-hypercube graph.

LINKS

Table of n, a(n) for n=1..31.

Eric Weisstein's World of Mathematics, Graph Skewness

Eric Weisstein's World of Mathematics, Hypercube Graph

Index entries for linear recurrences with constant coefficients, signature (5, -8, 4).

FORMULA

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

a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3).

a(n) = 4*A000337(n-2), with A000337(-1) = 0.

MATHEMATICA

Table[2^n (n - 3) + 4, {n, 20}]

LinearRecurrence[{5, -8, 4}, {0, 0, 4}, 20]

CoefficientList[Series[4 x^3/((1 - 2 x)^2 (1 - x)), {x, 0, 20}], x]

CROSSREFS

Cf. A000337.

Sequence in context: A287244 A123613 A006740 * A303011 A197426 A061981

Adjacent sequences:  A291523 A291524 A291525 * A291527 A291528 A291529

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein, Aug 25 2017

STATUS

approved

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Last modified July 11 20:03 EDT 2020. Contains 335652 sequences. (Running on oeis4.)