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A122605
Expansion of -x*(2*x - 1)*(2*x^2 - 1)*(x^3 + 2*x^2 - x - 1)/((x - 1)*(x^2 + x - 1)*(x^4 - 4*x^3 - 4*x^2 + x + 1)).
0
1, 0, 0, 0, 0, 0, 0, -1, -1, -7, -8, -35, -44, -154, -208, -637, -910, -2548, -3808, -9996, -15504, -38760, -62015, -149225, -245135, -572010, -961125, -2186886, -3746886, -8348172, -14547183, -31842580, -56309764, -121415344, -217478888, -462925232, -838520240, -1765205473, -3228800413
OFFSET
1,10
LINKS
Peter Steinbach, Golden fields: a case for the heptagon, Math. Mag. Vol. 70, No. 1, Feb. 1997, 22-31.
FORMULA
a(0)=1, a(1)=a(2)=a(3)=a(4)=a(5)=a(6)=0; for n>6, a(n) = a(n-1) + 6*a(n-2) - 5*a(n-3) - 10*a(n-4) + 6*a(n-5) + 4*a(n-6) - a(n-7). - Harvey P. Dale, May 02 2011
G.f.: -x*(2*x-1)*(2*x^2-1)*(x^3+2*x^2-x-1)/((x-1)*(x^2+x-1)*(x^4-4*x^3-4*x^2+x+1)). - Colin Barker, Nov 08 2012
MATHEMATICA
LinearRecurrence[{1, 6, -5, -10, 6, 4, -1}, {1, 0, 0, 0, 0, 0, 0}, 60] (* Harvey P. Dale, May 02 2011 *)
CROSSREFS
Cf. A066170.
Sequence in context: A042875 A154745 A048064 * A037953 A296636 A041106
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Feb 11 2007
Definition changed using Barker's g.f. by Bruno Berselli, Sep 19 2017
STATUS
approved