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A152994 Nine times hexagonal numbers: a(n) = 9*n*(2*n-1). 3
0, 9, 54, 135, 252, 405, 594, 819, 1080, 1377, 1710, 2079, 2484, 2925, 3402, 3915, 4464, 5049, 5670, 6327, 7020, 7749, 8514, 9315, 10152, 11025, 11934, 12879, 13860, 14877, 15930, 17019, 18144, 19305, 20502, 21735, 23004, 24309 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Sequence found by reading the line from 0, in the direction 0, 9,..., in the square spiral whose vertices are the generalized hendecagonal numbers A195160. - Omar E. Pol, Sep 18 2011

LINKS

Ivan Panchenko, Table of n, a(n) for n = 0..1000

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

FORMULA

a(n) = 18*n^2 - 9*n = A000384(n)*9 = A094159(n)*3.

a(n) = a(n-1) + 36*n - 27 for n>0, a(0)=0. - Vincenzo Librandi, Dec 15 2010

a(n) = Sum_{i = 2..10} P(i,n), where P(i,m) = m*((i-2)*m-(i-4))/2. - Bruno Berselli, Jul 04 2018

From G. C. Greubel, Sep 01 2019: (Start)

G.f.: 9*x*(1+3*x)/(1-x)^3.

E.g.f.: 9*x*(1+2*x)*exp(x). (End)

MAPLE

seq(9*n*(2*n-1), n=0..40); # G. C. Greubel, Sep 01 2019

MATHEMATICA

Table[9*n*(2*n-1), {n, 0, 40}] (* G. C. Greubel, Sep 01 2019 *)

PROG

(PARI) a(n)=9*n*(2*n-1) \\ Charles R Greathouse IV, Jun 17 2017

(MAGMA) [9*n*(2*n-1): n in [0..40]]; // G. C. Greubel, Sep 01 2019

(Sage) [9*n*(2*n-1) for n in (0..40)] # G. C. Greubel, Sep 01 2019

(GAP) List([0..40], n-> 9*n*(2*n-1)); # G. C. Greubel, Sep 01 2019

CROSSREFS

Cf. A000384, A094159.

Similar sequences are listed in A316466.

Sequence in context: A224484 A225791 A093846 * A034719 A013567 A073974

Adjacent sequences:  A152991 A152992 A152993 * A152995 A152996 A152997

KEYWORD

nonn,easy

AUTHOR

Omar E. Pol, Dec 22 2008

STATUS

approved

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Last modified September 20 16:30 EDT 2019. Contains 327242 sequences. (Running on oeis4.)