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A027166 a(n) = Sum_{0<=j<=i<=n} A027157(i, j). 1
1, 4, 14, 36, 103, 248, 684, 1624, 4445, 10524, 28762, 68060, 185955, 439984, 1202072, 2844144, 7770361, 18384884, 50228454, 118841812, 324681887, 768205608, 2098776772, 4965759176, 13566706389, 32099171980, 87696568754, 207492309516, 566879531803 (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 (2,5,-12,9,-6,3).

FORMULA

From Colin Barker, Feb 20 2016: (Start)

a(n) = 2*a(n-1)+5*a(n-2)-12*a(n-3)+9*a(n-4)-6*a(n-5)+3*a(n-6) for n>5.

G.f.: (1+x)^2 / ((1-x)^2*(1-6*x^2-3*x^4)).

(End)

MATHEMATICA

LinearRecurrence[{2, 5, -12, 9, -6, 3}, {1, 4, 14, 36, 103, 248}, 30] (* Harvey P. Dale, Apr 18 2019 *)

PROG

(PARI) Vec((1+x)^2/((1-x)^2*(1-6*x^2-3*x^4)) + O(x^40)) \\ Colin Barker, Feb 20 2016

CROSSREFS

Partial sums of A027164.

Sequence in context: A128758 A258343 A317148 * A126943 A209399 A192974

Adjacent sequences:  A027163 A027164 A027165 * A027167 A027168 A027169

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified December 5 06:51 EST 2020. Contains 338944 sequences. (Running on oeis4.)