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A033566 a(n) = (2*n+1) * (4*n-1). 8
-1, 9, 35, 77, 135, 209, 299, 405, 527, 665, 819, 989, 1175, 1377, 1595, 1829, 2079, 2345, 2627, 2925, 3239, 3569, 3915, 4277, 4655, 5049, 5459, 5885, 6327, 6785, 7259, 7749, 8255, 8777, 9315, 9869, 10439, 11025, 11627, 12245, 12879, 13529, 14195, 14877, 15575, 16289, 17019, 17765 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

FORMULA

a(n) = A005408(n) * A004767(n-1). - Michel Marcus, Oct 03 2016

From G. C. Greubel, Oct 12 2019: (Start)

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

E.g.f.: (-1 + 10*x + 8*x^2)*exp(x). (End)

MAPLE

seq((2*n+1)*(4*n-1), n=0..50); # G. C. Greubel, Oct 12 2019

MATHEMATICA

Table[(2*n+1)*(4*n-1), {n, 0, 50}] (* G. C. Greubel, Oct 12 2019 *)

PROG

(PARI) a(n) = (2*n+1) * (4*n-1); \\ Michel Marcus, Oct 03 2016

(MAGMA) [(2*n+1)*(4*n-1): n in [0..50]] # G. C. Greubel, Oct 12 2019

(Sage) [(2*n+1)*(4*n-1) for n in range(50)] # G. C. Greubel, Oct 12 2019

(GAP) List([0..50], n-> (2*n+1)*(4*n-1)); # G. C. Greubel, Oct 12 2019

CROSSREFS

Cf. A004767, A005408.

Sequence in context: A085366 A304913 A173245 * A226755 A022275 A071398

Adjacent sequences:  A033563 A033564 A033565 * A033567 A033568 A033569

KEYWORD

sign,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

Terms a(37) onward added by G. C. Greubel, Oct 12 2019

STATUS

approved

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Last modified December 2 11:44 EST 2021. Contains 349440 sequences. (Running on oeis4.)