OFFSET
1,1
COMMENTS
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,5,0,-10,0,10,0,-5,0,1).
FORMULA
a(n) = denominator of the reduced -16/(n*(n-2)*(n+2)*(n-4)).
a(2n) = A052762(n+1).
a(n) = 5*a(n-2) -10*a(n-4) +10*a(n-6) -5*a(n-8) +a(n-10) for n>15. - R. J. Mathar, Mar 27 2010
a(n) = -(-17+15*(-1)^n)*(n*(16-4*n-4*n^2+n^3))/32 for n>3. - Colin Barker, Nov 11 2014
G.f.: 3*x*(10*x^12-50*x^10+105*x^8-160*x^6-8*x^5-40*x^4+10*x^2-3) / ((x-1)^5*(x+1)^5). - Colin Barker, Nov 11 2014
EXAMPLE
f(5) = -16/(7*5*3*1) = -16/105, denominator a(5) = 105.
f(6) = -16/(8*6*4*2) = -1/24, denominator a(6) = 24.
MAPLE
f(n) := n -> (1/((n/4)+(n^2/4)-(n^3/16)-1))/n;
MATHEMATICA
Join[{9, 0, 15, 0}, Denominator[Table[-(16/(n (n^3-4 n^2-4 n+16))), {n, 5, 40}]]] (* Harvey P. Dale, Nov 06 2011 *)
PROG
(PARI) Vec(3*x*(10*x^12-50*x^10+105*x^8-160*x^6-8*x^5-40*x^4+10*x^2-3)/((x-1)^5*(x+1)^5) + O(x^100)) \\ Colin Barker, Nov 11 2014
CROSSREFS
KEYWORD
frac,nonn,easy
AUTHOR
Steven J. Forsberg, Apr 25 2006
EXTENSIONS
Clearer definition from R. J. Mathar, Mar 27 2010
STATUS
approved