41952

Appears in sequences

• G.f.: { ( Product_{j=1..infinity} (1-x^j) - 1 )/x }^24.at n=5A006665
• a(n) = 3*n^3 + n^2 - 4*n.at n=24A083127
• Numbers k such that the sum of the digits of k^sigma(k) is divisible by k.at n=22A109658
• Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives z numbers.at n=5A125492
• Wiener index of the n-web graph.at n=31A180576
• Binomial transform of A215495(n).at n=13A217988
• Number of length 2+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third.at n=13A248463
• Numbers that belong to at least one amicable tuple.at n=35A255215
• Least number x such that x^n has n digits equal to k. Case k=4.at n=30A285451
• Number of parts in all partitions of n with largest multiplicity three.at n=36A320373
• a(n) is the permanent of a square matrix M(n) whose general element M_{i,j} is defined by floor((j - i + 1)/2).at n=8A350549
• Triangle read by rows: T(k,n) (k >= 0, n = 0, ..., k) = number of tilings of a k X n rectangle using 2 X 2 tiles, right trominoes and dominoes.at n=20A354010
• Number of tilings of an n X n square using right trominoes, dominoes, and 2 X 2 tiles.at n=5A354119
• a(n) = (n^2 - n + 2) * (5*n^2 - 5*n + 2) / 4.at n=13A380353
• Integers k such that there exists an integer 0<m<k such that (1/sigma(m)^2 + 1/sigma(k)^2)*(m+k)^2 = 1.at n=11A383964
• Numbers z such that there exist two integers 0<x<=y<=z such that (x^2/sigma(x)^2 + y^2/sigma(y)^2 + z^2/sigma(z)^2) * (x + y + z)^2 = x^2 + y^2 + z^2.at n=9A385749
• Numbers z such that there exist two integers 0<x<=y<=z such that sigma(x)*sigma(y)*sigma(z) = (x + y + z)^3.at n=11A386010