A347319 a(n) = (2*n+1)*(n^3-2*n^2+n+1).

1, 3, 15, 91, 333, 891, 1963, 3795, 6681, 10963, 17031, 25323, 36325, 50571, 68643, 91171, 118833, 152355, 192511, 240123, 296061, 361243, 436635, 523251, 622153, 734451, 861303, 1003915, 1163541, 1341483, 1539091, 1757763, 1998945, 2264131, 2554863, 2872731, 3219373, 3596475, 4005771

Offset

0,2

Links

Table of n, a(n) for n=0..38.

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Formula

From Chai Wah Wu, Sep 12 2021: (Start)

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 4.

G.f.: (-3*x^4 - 36*x^3 - 10*x^2 + 2*x - 1)/(x - 1)^5. (End)

Prog

(Python)
def A347319(n): return n*(n**2*(2*n - 3) + 3) + 1 # Chai Wah Wu, Sep 12 2021
(PARI) a(n)=2*n+1)*(n^3-2*n^2+n+1 \\ Charles R Greathouse IV, Oct 21 2022

Crossrefs

A bisection of A146212, analogous to A344866 and A344907.

Sequence in context: A336743 A034954 A077783 * A047019 A099251 A364740

Adjacent sequences: A347316 A347317 A347318 * A347320 A347321 A347322

Keyword

nonn,easy

Author

N. J. A. Sloane, Sep 12 2021

Status

approved