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A016150 Expansion of 1/((1-4x)(1-7x)). 2
1, 11, 93, 715, 5261, 37851, 269053, 1899755, 13363821, 93808891, 657710813, 4608169995, 32273967181, 225984879131, 1582162589373, 11076211867435, 77537778039341, 542781626144571, 3799540102488733 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (11,-28).

FORMULA

a(n) = (7^(n+1)-4^(n+1))/3. - Barry E. Williams, Jan 13 2000

a(n) = 11*a(n-1)-28*a(n-2) for n>0, a(0)=1. - Barry E. Williams, Jan 13 2000

a(n) = sum( k=0..n, 7^k*4^(n-k) ). [Bruno Berselli, Aug 07 2013]

MATHEMATICA

Join[{a=1, b=11}, Table[c=11*b-28*a; a=b; b=c, {n, 60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 31 2011 *)

CoefficientList[Series[1 / ((1 - 4 x) (1 - 7 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jun 24 2013 *)

PROG

(Sage) [lucas_number1(n, 11, 28) for n in xrange(1, 20)] /* Zerinvary Lajos, Apr 27 2009 */

(PARI) Vec(1/((1-4*x)*(1-7*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012

(MAGMA) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-4*x)*(1-7*x)))); // Vincenzo Librandi, Jun 24 2013

CROSSREFS

Sequence in context: A044643 A025507 A081575 * A115203 A164547 A298925

Adjacent sequences:  A016147 A016148 A016149 * A016151 A016152 A016153

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified December 17 03:10 EST 2018. Contains 318192 sequences. (Running on oeis4.)