2097136

Appears in sequences

• Sum of binary numbers with n 1's and one (possibly leading) 0.at n=16A059672
• a(n) = the least positive integer k such that Omega(n+k) = Omega(k)+n, where Omega(m) (A001222) denotes the number of prime factors of m, counting multiplicity.at n=15A076158
• Let S(n)=Sigma(n)/2. Numbers n such that S(S(n))=n, 1/2-Sociable number of order 1 or 2.at n=34A113791
• Triangle read by rows: row n lists the divisors of n-th perfect number A000396(n) that are multiples of n-th Mersenne prime A000668(n).at n=34A139247
• a(n) = 16*(2^n - 1).at n=17A175164
• Numbers n such that 8^9 + n^2 is a square.at n=8A180972
• Largest members of fully k-sociable cycles of order r.at n=31A183023
• Non-unitary amicable numbers.at n=31A259037
• Larger of a non-unitary amicable pair.at n=14A259039
• Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 621", based on the 5-celled von Neumann neighborhood.at n=20A289961
• Nonunitary superperfect numbers: numbers k such that nusigma(nusigma(k)) = k, where nusigma(k) = sigma(k) - usigma(k) is the sum of nonunitary divisors of k (A048146).at n=35A329884
• Numbers that are either already perfect, or a perfect number is eventually reached if we start doubling them.at n=32A341622
• Greater member of Carmichael's variant of amicable pair: numbers k < m such that s(k) = m and s(m) = k, where s(k) = A371418(k).at n=15A371420