A301687 - OEIS

A301687

Partial sums of A301686.

1, 6, 13, 27, 44, 63, 91, 120, 151, 193, 234, 277, 333, 386, 441, 511, 576, 643, 727, 804, 883, 981, 1070, 1161, 1273, 1374, 1477, 1603, 1716, 1831, 1971, 2096, 2223, 2377, 2514, 2653, 2821, 2970, 3121, 3303, 3464, 3627, 3823, 3996, 4171, 4381, 4566, 4753, 4977, 5174, 5373, 5611, 5820, 6031, 6283, 6504, 6727, 6993, 7226, 7461, 7741

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OFFSET

0,2

COMMENTS

Linear recurrence and g.f. confirmed by Shutov/Maleev link in A301686. - Ray Chandler, Aug 30 2023

LINKS

Ray Chandler, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (1, 0, 2, -2, 0, -1, 1).

FORMULA

From Chai Wah Wu, Feb 03 2021: (Start)

a(n) = a(n-1) + 2*a(n-3) - 2*a(n-4) - a(n-6) + a(n-7) for n > 6.

G.f.: (-x^6 - 5*x^5 - 7*x^4 - 12*x^3 - 7*x^2 - 5*x - 1)/((x - 1)^3*(x^2 + x + 1)^2). (End)