1285956

Appears in sequences

• Refactorable numbers k such that the number of odd divisors r is odd, the number of even divisors s is even and both r and s are divisors of k.at n=15A120349
• E.g.f. satisfies: A(x,y) = exp(x*y*exp(x*A(x,y))).at n=52A161552
• Number of n X 4 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=26A208138
• Product of the nonzero digits (in base 10) of n^5.at n=12A218311
• Triangle (sans apex) of coefficients of terms of the form (eM_1)^j*(eM_2)^k re construction of triangle A287768.at n=49A288842
• a(n) = sigma_3(n)^2.at n=9A356534
• Nonprimes k such that sopfr(k) = rad(k), where sopfr(k) is sum of the prime factors of k (counting multiplicity), and rad(k) is the product of its distinct prime factors.at n=20A386916