73749

Appears in sequences

• Numbers k such that sigma(k-phi(k)) = phi(k).at n=19A070170
• G.f.: A(x) = exp( Sum_{n>=1} A162552(n)^2*x^n/n ) where the l.g.f. of A162552 is the log of the characteristic function of the squares.at n=24A162553
• Odd numbers m such that sigma(x) = m has more than 1 solution.at n=26A300869
• Number of nX3 0..1 arrays with every element unequal to 1, 2, 4, 6 or 7 king-move adjacent elements, with upper left element zero.at n=13A305092
• Odd numbers k that can be factored to such a pair of coprime factors x and y that A347381(k) < min(A347381(x), A347381(y)).at n=32A347390
• Number of commuting pairs of equivalence relations on [n].at n=7A354458
• Sum of divisors of those odd squares k for which A379113(k) > 1, i.e., k that have a proper unitary divisor d > 1 such that A048720(A065621(sigma(d)),sigma(k/d)) is equal to sigma(k).at n=5A379125