556544

Appears in sequences

• Numbers m such that 2*m - sigma(m) is a divisor of m and greater than one, where sigma = A000203 is the sum of divisors.at n=27A060326
• a(1) = 9, a(2) = 44, a(n) = 4*(a(n-1) + a(n-2)) (n >=3).at n=7A228603
• a(n) = q^2*(q^2+2*q-1)/2, where q = n-th prime power A000961(n).at n=18A229739
• a(n) = (n^4 + 2*n^3 - n^2)/2.at n=32A255499
• Deficient-perfect numbers: Deficient numbers n such that n/(2n-sigma(n)) is an integer.at n=47A271816
• Numbers k whose deficiency is 64: 2k - sigma(k) = 64.at n=13A275997