33550337

Properties

Appears in sequences

• Numbers k such that j(k)*phi(k) = s(phi(k)), where j(k) = A033831(k), s(k) = sigma(k) - k.at n=24A033855
• "Right perfect numbers": primes of the form 1 + a perfect number.at n=2A061644
• Primes p such that cototient(totient(p)) = A070556(p) is a power of 2.at n=22A070806
• a(n) = (-1)^(n+1) * coefficient of x^n in Sum_{k>=1} x^k/(1+2*x^k).at n=25A081295
• Primes of the form 1 + multiple perfect number.at n=8A093034
• a(n) = 2^(n-1)*(2^n - 1) + 1.at n=13A134169
• Nearest-neighbors of perfect numbers.at n=9A135606
• Perfect numbers plus 1.at n=4A135629
• Numbers n such that sigma(n) - tau(n) is a perfect number.at n=8A219036
• Primes of the form q*2^h + 1, where q is a Mersenne prime.at n=17A336117
• Numbers m such that there exist positive integers i <= m and j >= m such that m = Sum_{k=i..j} A001065(k), where A001065(k) = sum of the proper divisors of k, and i and j do not both equal m.at n=32A346140
• a(n) = Sum_{d|n} (-1)^(d-1) * 2^(n/d-1).at n=25A373275
• Prime numbersat n=2063450