21411

Appears in sequences

• Numbers k that divide s(k), where s(1)=1, s(j)=13*s(j-1)+j.at n=31A014861
• Multiplicity of highest weight (or singular) vectors associated with character chi_145 of Monster module.at n=39A034533
• n satisfying sigma(n+1) = sigma(n-1).at n=27A055574
• Numbers whose product of decimal digits equals its sum of binary digits.at n=31A064003
• Numbers k such that sigma(k-1) divides sigma(k+1).at n=33A067130
• a(n) = (2*n^3 + 5*n^2 - 7*n)/2.at n=26A162261
• Number of strings of n+2 numbers x(i) in -6..6 with the sum of x(i) equal to zero and the sums of x(i)*x(i+1) and x(i)*x(i+2) equal to each other.at n=4A184058
• T(n,k) = Number of strings of n+2 numbers x(i) in -k..k with the sum of x(i) equal to zero and the sums of x(i)*x(i+1) and x(i)*x(i+2) equal to each other.at n=49A184061
• a(n) = n*(14*n + 3).at n=39A195025
• Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=28A223137
• Numbers k such that sigma(k+1) divides sigma(k-1).at n=28A227304
• Least number k such that the determinant of the circulant matrix formed by its decimal digits is equal to k/n.at n=38A323485
• Number of Deutsch paths with peaks at odd height.at n=16A350114
• Expansion of (x/(8 * (1-x))) * d/dx(theta_3(x)^4).at n=37A374535
• a(n) is the number of five element sets of distinct integer-sided trapezoids whose base angles are 60 degrees that fill an equilateral triangular grid of side n units.at n=20A391498