125969

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-4)/2.at n=19A048060
• Smallest solution m to (n+1)*phi(m) = n*sigma(m), or -1 if no solution exists.at n=46A065824
• a(n) = A065824(A047845(n+1)).at n=23A065884
• a(n) = binomial(n+8,8) - 1.at n=12A165618
• a(n) = number of nonempty subsets S of {1,2,...,n} such that (number of nonprimes in S) = (number of primes in S).at n=20A369854