OFFSET
0,1
COMMENTS
If Y is a 5-subset of an n-set X then, for n>=13, a(n-13) is the number of 9-subsets of X having at most one element in common with Y. - Milan Janjic, Dec 08 2007
LINKS
Index entries for linear recurrences with constant coefficients, signature (10,-45,120,-210,252,-210,120,-45,10,-1).
FORMULA
a(n) = (n+45)*binomial(n+8, 8)/9.
a(n) = 5*b(n)-4*b(n-1), with b(n) = A000582(n+9) = binomial(n+9, 9).
G.f.: (5-4*x)/(1-x)^10.
MATHEMATICA
CoefficientList[Series[(5-4x)/(1-x)^10, {x, 0, 40}], x] (* Harvey P. Dale, Jan 06 2020 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Jul 16 2004
STATUS
approved