OFFSET
0,2
COMMENTS
LINKS
T. D. Noe, Table of n, a(n) for n = 0..5000
FORMULA
a(n) = n+1-A048277(n). - R. J. Mathar, Jan 18 2018
EXAMPLE
If n=20, then C(20, k) is squarefree for k = 0,2,4,8,12,16,18,20, that is, for 8 cases of k, so a(20)=8.
MAPLE
A048276 := proc(n)
local a, k ;
a := 0 ;
for k from 0 to n do
if issqrfree(binomial(n, k)) then
a := a+1 ;
end if;
end do:
a ;
end proc:
seq(A048276(n), n=0..40) ; # R. J. Mathar, Jan 18 2018
MATHEMATICA
Table[Length[Select[Binomial[n, Range[0, n]], SquareFreeQ[#] &]], {n, 0, 100}]
PROG
(PARI) a(n) = sum(k=0, n, issquarefree(binomial(n, k))); \\ Michel Marcus, Dec 19 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved