A379745 - OEIS

A379745

a(n) = Sum_{k=1..n-1} binomial(n, k)*2^(n-k-1)*(k-1).

0, 0, 3, 20, 95, 394, 1519, 5592, 19935, 69398, 237215, 799204, 2661295, 8776962, 28714191, 93300656, 301392575, 968682286, 3099626047, 9879746748, 31382108175, 99375452570, 313814790383, 988511766280, 3106741678495, 9743852563014, 30502457048799, 95320102780052, 297398570349935, 926510631296818, 2882476923066895, 8956266393600864, 27795307127744895, 86165447371545182, 266834924374534271

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..35.

Index entries for linear recurrences with constant coefficients, signature (10,-38,68,-57,18).

FORMULA

a(n) = (3^(n-1)-1)*(n-3)/2 + 2^(n-1) - 1.

MATHEMATICA

LinearRecurrence[{10, -38, 68, -57, 18}, {0, 0, 3, 20, 95}, 35] (* James C. McMahon, Jan 07 2025 *)

CROSSREFS

Sequence in context: A015529 A278319 A305203 * A246150 A000948 A074831

Adjacent sequences: A379742 A379743 A379744 * A379746 A379747 A379748

KEYWORD

nonn,easy

AUTHOR

Ocean Wong, Jan 01 2025

STATUS

approved