4194296

Appears in sequences

• Numbers n such that uphi(sigma(n)) = n, where the uphi is the unitary phi function A047994.at n=36A030164
• Numerators of coefficients in expansion of x^-2*(1-exp(-2*x))^2.at n=18A104042
• a(n) = Sum_{k=0..n} floor(C(n,k)/2).at n=23A120739
• a(n) = 8*(2^n - 1).at n=18A159741
• Row sums of triangle A166455.at n=21A166456
• Numbers n such that 8^9 + n^2 is a square.at n=9A180972
• Non-unitary amicable numbers.at n=33A259037
• Larger of a non-unitary amicable pair.at n=16A259039
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 259", based on the 5-celled von Neumann neighborhood.at n=21A280369
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 633", based on the 5-celled von Neumann neighborhood.at n=23A283403
• Least d > 0 such that both Q = M + 2d and R = M + (M^2-1)/(Q-M) are prime, where M = 2^n - 1 = A000225(n), or 0 if there is no such d.at n=38A320875
• 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=37A329884
• Numbers that are either already perfect, or a perfect number is eventually reached if we start doubling them.at n=36A341622