137980domain: NAppears in sequencesa(n) = Sum_{k=0..7} binomial(n,k).at n=20A008860(1/n) times the sum of the elements of all subsets of [n] whose sum is divisible by n.at n=18A309128a(n) = number of subsets of {1,2,...,n} that contain more primes than nonprimes.at n=20A369780a(n) = Sum_{k=0..n} binomial(3*n-1,k).at n=7A387033