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A071246 a(n) = n*(n - 1)*(2*n^2 + n + 2)/6. 1
0, 0, 4, 23, 76, 190, 400, 749, 1288, 2076, 3180, 4675, 6644, 9178, 12376, 16345, 21200, 27064, 34068, 42351, 52060, 63350, 76384, 91333, 108376, 127700, 149500, 173979, 201348, 231826, 265640, 303025, 344224, 389488, 439076, 493255, 552300, 616494 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

T. A. Gulliver, Sequences from Arrays of Integers, Int. Math. Journal, Vol. 1, No. 4, pp. 323-332, 2002.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..2000

FORMULA

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5), n > 4, a(0)=0, a(1)=0, a(2)=4, a(3)=23, a(4)=76. [Yosu Yurramendi, Sep 03 2013]

From Indranil Ghosh, Apr 05 2017: (Start)

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

E.g.f.: exp(x)*(x^2)*(12 + 11x + 2x^2)/6.

(End)

MATHEMATICA

CoefficientList[Series[-(4x^2 + 3x^3 + x^4)/(x - 1)^5, {x, 0, 50}], x] (* or *) Table[n*(n - 1)*(2*n^2 + n + 2)/6, {n, 0, 50}] (* Indranil Ghosh, Apr 05 2017 *)

PROG

(MAGMA) [n*(n-1)*(2*n^2+n+2)/6: n in [0..40]]; // Vincenzo Librandi, Jun 14 2011

(PARI) a(n) = n*(n - 1)*(2*n^2 + n + 2)/6; \\ Indranil Ghosh, Apr 05 2017

(Python) def a(n): return n*(n - 1)*(2*n**2 + n + 2)/6 # Indranil Ghosh, Apr 05 2017

CROSSREFS

Sequence in context: A132112 A226411 A226342 * A219933 A304305 A316204

Adjacent sequences:  A071243 A071244 A071245 * A071247 A071248 A071249

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jun 12 2002

STATUS

approved

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Last modified October 23 03:21 EDT 2019. Contains 328335 sequences. (Running on oeis4.)