A341549 a(n) = Sum_{k=1..n} (-1)^(n+k)*A087322(n,k).

3, 6, 23, 50, 131, 294, 687, 1530, 3419, 7502, 16391, 35490, 76467, 163830, 349535, 742730, 1572875, 3320478, 6990519, 14680050, 30758243, 64312646, 134217743, 279620250, 581610171, 1207959534, 2505397607, 5189752130, 10737418259, 22190664342

Offset

1,1

Links

Table of n, a(n) for n=1..30.

Index entries for linear recurrences with constant coefficients, signature (3,1,-7,0,4).

Formula

a(n) = ((n + 1)*2^(n + 2) - 3 + (4*n + 1)*(-1)^(n + 1))/6.

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

Crossrefs

Cf. A087322.

Sequence in context: A090910 A256674 A176424 * A151443 A148643 A240646

Adjacent sequences: A341546 A341547 A341548 * A341550 A341551 A341552

Keyword

nonn,easy

Author

Petros Hadjicostas, Feb 15 2021

Status

approved