195216

Appears in sequences

• Numbers k such that k | sigma_7(k) - phi(k)^7.at n=28A055701
• Triangle read by rows, T(n,k) matrix inverse of A256550, for n>=0 and 0<=k<=n.at n=48A256551
• The number of 3D walks of semilength n in a quadrant returning to the origin.at n=5A302178
• The number of 3D walks of length n in an octant returning to axis of origin.at n=10A302179
• E.g.f.: C(x,k) = 1 + Integral S(x,k)*D(x,k)^2 dx, such that C(x,k)^2 - S(x,k)^2 = 1, and D(x,k)^2 - k^2*S(x,k)^2 = 1, as a triangle of coefficients read by rows.at n=17A322231
• E.g.f.: D(x,k) = dn( i * Integral C(x,k) dx, k) such that C(x,k) = cn( i * Integral C(x,k) dx, k), where D(x,k) = Sum_{n>=0} Sum_{j=0..n} T(n,j) * x^(2*n)*k^(2*j)/(2*n)!, as a triangle of coefficients T(n,j) read by rows.at n=18A325222
• Numbers k such that s(k) = 3*k, where s(k) is the sum of divisors of k that have a square factor (A162296).at n=4A357493