425880

Appears in sequences

• Unitary superperfect numbers: numbers n such that usigma(usigma(n)) = 2*n, where usigma(n) is the sum of unitary divisors of n (A034448).at n=12A038843
• Numbers with prime factorization pqr^2s^2t^3.at n=28A190386
• Triangle read by rows: T(n,k) = number of pairs of partitions of n that have block distance k (n >= 2, 2 <= k <= n).at n=30A193297
• Number of 3 X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 1 1 1 vertically.at n=12A207929
• Number of (n+2)X(3+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=2A258506
• T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=12A258511
• Number of (3+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the diagonal and antidiagonal minus the sum of the medians of the central row and column nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=2A258513
• a(n) = Product_{d|n} T(d) where T(x) = x*(x+1)/2 = A000217(x) = x-th triangular number.at n=38A275786
• Numbers m that divide sigma(sigma(m) - m) where sigma is the sum of divisors function (A000203).at n=31A300658
• E.g.f. A(x) satisfies A(x) = exp( x^3 * A(x) / (1-x)^3 ) / (1-x).at n=7A389870