181656

Appears in sequences

• Prime power perfect numbers: If n = Product p_i^r_i let PPsigma(n) = Product {Sum p_i^s_i, 2<=s_i<=r_i, s_i is prime}; sequence gives numbers k such that PPsigma(k) = 2*k.at n=8A096290
• Number of monomials in discriminant of polynomial x^n + a_{n-2} x^{n-2} + ... + a_0.at n=10A138800
• Numbers with prime factorization p^2*q^3*r^3 where p, q, and r are distinct primes.at n=20A190106