OFFSET
0,3
FORMULA
a(n) = sum((-1)^(n-k)*floor(sqrt(binomial(2*k,k))),k=0..n).
MATHEMATICA
Table[Sum[(-1)^(n-k)Floor[Sqrt[Binomial[2k, k]]], {k, 0, n}], {n, 0, 100}]
PROG
(Maxima) makelist(sum((-1)^(n-k)*floor(sqrt(binomial(2*k, k))), k, 0, n), n, 0, 24);
CROSSREFS
KEYWORD
nonn
AUTHOR
Emanuele Munarini, Jul 07 2011
STATUS
approved