356962domain: NAppears in sequencesa(n) = floor((2^n)/(2n-1)).at n=23A191631a(n) = floor((-1 + 4^n)/(-1 + 4*n)).at n=11A191640(1/n)*A204991(n).at n=46A204992Number of subsets of {1, 3, ..., 2*n-1} which sum to 0 modulo 2*n-1.at n=23A334125a(n) are the denominators corresponding to A370825(n).at n=22A370826