OFFSET
0,4
MAPLE
C7:=proc(r) local t1, n;
t1:=mul((1-x^n)^r, n=1..2*r+2);
series(t1, x, 2*r+1);
coeff(%, x, 2*r);
end;
[seq(C7(i), i=0..30)];
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Oct 04 2015
STATUS
approved