OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
J. Riordan, The distribution of crossings of chords joining pairs of 2n points on a circle, Math. Comp., 29 (1975), 215-222.
J. Riordan, The distribution of crossings of chords joining pairs of 2n points on a circle, Math. Comp., 29 (1975), 215-222. [Annotated scanned copy]
Index entries for linear recurrences with constant coefficients, signature (4,-8,4,-1).
FORMULA
G.f.: (x+1) / (x^4-4*x^3+8*x^2-4*x+1). - Colin Barker, Jul 09 2015
MAPLE
A259860 := proc(n)
if n <= 7 then
op(n+1, [1, 5, 12, 12, -29, -169, -408, -408, 985, 5741, 13860, 13860]) ;
else
-34*procname(n-4)-procname(n-8) ;
fi ;
end proc: # R. J. Mathar, Jun 24 2024
MATHEMATICA
LinearRecurrence[{4, -8, 4, -1}, {1, 5, 12, 12}, 40] (* Harvey P. Dale, Mar 14 2016 *)
PROG
(PARI) Vec((x+1)/(x^4-4*x^3+8*x^2-4*x+1) + O(x^50)) \\ Colin Barker, Jul 09 2015
CROSSREFS
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Jul 08 2015
STATUS
approved