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A135706 a(n) = n*(5*n-3). 11
0, 2, 14, 36, 68, 110, 162, 224, 296, 378, 470, 572, 684, 806, 938, 1080, 1232, 1394, 1566, 1748, 1940, 2142, 2354, 2576, 2808, 3050, 3302, 3564, 3836, 4118, 4410, 4712, 5024, 5346, 5678, 6020, 6372, 6734, 7106, 7488, 7880, 8282, 8694, 9116, 9548, 9990, 10442 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Twice heptagonal numbers. - Omar E. Pol, May 14 2008

REFERENCES

L. Hogben, Choice and Chance by Cardpack and Chessboard. Vol. 1, Chanticleer Press, NY, 1950, p. 36.

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

Binomial transform of [2, 12, 10, 0, 0, 0,...]. - Gary W. Adamson, Mar 05 2008

a(n) = a(n-1) + 10*n - 8 (with a(0)=0). - Vincenzo Librandi, Nov 24 2010

a(n) = A131242(10n+1). - Philippe Deléham, Mar 27 2013

From G. C. Greubel, Oct 29 2016: (Start)

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

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

E.g.f.: x*(2 + 5*x)*exp(x). (End)

MATHEMATICA

LinearRecurrence[{3, -3, 1}, {0, 2, 14}, 25] (* or *) Table[n*(5*n-3), {n, 0, 25}] (* G. C. Greubel, Oct 29 2016 *)

PROG

(PARI) a(n)=n*(5*n-3) \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

a(n)=A000566(n)*2. - Omar E. Pol, May 14 2008

Cf. numbers of the form n*(n*k-k+4))/2 listed in A226488 (this sequence is the case k=10). - Bruno Berselli, Jun 10 2013

Sequence in context: A128126 A134647 A004117 * A091520 A218546 A254964

Adjacent sequences:  A135703 A135704 A135705 * A135707 A135708 A135709

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Mar 04 2008, Mar 05 2008

STATUS

approved

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Last modified October 22 23:18 EDT 2018. Contains 316518 sequences. (Running on oeis4.)