OFFSET
0,6
FORMULA
G.f.: 1/sqrt((1-x^2)^2+x^6-2*x^5-2*x^3).
D-finite with recurrence: n*a(n) -2*(n-1)*a(n-2)-(2*n-3)*a(n-3)+(n-2)*a(n-4) -(2*n-5)*a(n-5) +(n-3)*a(n-6) = 0. - R. J. Mathar, Jan 21 2020
MAPLE
A298567 := proc(n)
option remember;
if n < 7 then
op(n+1, [1, 0, 1, 1, 1, 4, 2]) ;
else
-2*(n-1)*procname(n-2)-(2*n-3)*procname(n-3)+(n-2)*procname(n-4)
-(2*n-5)*procname(n-5)+(n-3)*procname(n-6) ;
-%/n ;
end if;
end proc: # R. J. Mathar, Jan 21 2020
PROG
(Maxima)
a(n):=sum(binomial(n-k, 2*k-n)^2, k, 0, 2*n/3);
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Kruchinin, Jan 21 2018
STATUS
approved