OFFSET
1,1
COMMENTS
a(n) is odd since binomial(2*k,k) is even for k>0. - Chai Wah Wu, Nov 30 2023
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..10000
MAPLE
isa := n -> irem(irem(binomial(2*n, n), n), 2) = 1:
select(isa, [seq(1..507, 2)]); # Peter Luschny, Nov 30 2023
MATHEMATICA
A367782Q[n_]:=OddQ[Mod[Binomial[2n, n], n]];
Select[Range[1000], A367782Q] (* Paolo Xausa, Dec 01 2023 *)
PROG
(PARI) for(n=1, 510, if(bitand(binomial(2*n, n)%n, 1), print1(n, ", ")));
(Python)
from math import comb
from itertools import count, islice
def A367782_gen(startvalue=1): # generator of terms >= startvalue
return filter(lambda n: (comb(n<<1, n)%n)&1, count(max(startvalue+(startvalue&1^1), 1), 2))
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt, Nov 30 2023
STATUS
approved