30258

Appears in sequences

• A054221 without cubes.at n=19A054224
• Even refactorable numbers k such that the number r of odd divisors of k and the number s of even divisors of k are both odd divisors of k.at n=18A120361
• Non-deficient numbers with odd sigma such that the sum of the even divisors is twice the sum of the odd divisors.at n=23A171642
• a(n) = a(n-1) + a(n-2) - [a(n-3)/4] - [a(n-4)/2] - [a(n-5)/4].at n=33A173564
• a(n) = a(n-1) + a(n-2) - [a(n-2)/4] - [a(n-4)/2] - [a(n-6)/4].at n=36A173599
• Numbers n such that the sum_i (d_i^i) of the i-th powers of their sorted divisors d_1< d_2<...< n is prime.at n=7A180852
• a(n) = 18*n^2.at n=41A195321
• Numbers k such that sigma(k) > 2*k and A003415(sigma(k)) < k, where A003415 is the arithmetic derivative, and sigma is the sum of divisors function.at n=44A347889
• Numbers k such that (A276086(k)/s)^s >= k^(s-1) and A276086(k) <= A003415(k), where A003415 is the arithmetic derivative, A276086 is the primorial base exp-function, and s = bigomega(k).at n=42A370128
• Refactorable numbers that are twice a square.at n=31A376114