280423domain: NAppears in sequencesNumber of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= n/2.at n=24A047163Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-1)/2.at n=24A047174The number of prime-indexed primes below 2^n.at n=26A374151