80104

Appears in sequences

• Number of n-input 2-output switching networks under action of GL(n,2) on the inputs and complementing group C(2,2) on the outputs.at n=3A000847
• Fibonacci sequence beginning 0, 31.at n=18A022365
• Numbers k such that phi(k) = sigma(core(k)) where phi(k) is the Euler totient function, sigma(k) the sum of divisors of k and core(k) the squarefree part of k (the smallest integer such that k*core(k) is a square).at n=10A069552
• Expansion of x^4*(2+x)/((1+x)*(1-x)^5).at n=31A082289
• Numbers n such that sigma(n) = 5*phi(n).at n=12A136547
• A triangular sequence of six back recursive polynomial that are Hermite H(x,n) like and alternating orthogonal on domain {-Infinity,Infinity} and weight function Exp[ -x^2/2]:k=6 P(x, n) = Sum[If[Mod[m, 2] == 1, (m + 1)*x^m*P(x, n - m), n^(m/2)*P(x, n - m)], {m, 1, k}].at n=48A138093
• A triangular sequence of eight back recursive polynomials that are Hermite H(x,n) like and alternating orthogonal on domain {-Infinity,Infinity} and weight function Exp[ -x^2/2]:k=8 P(x, n) = Sum[If[Mod[m, 2] == 1, (m + 1)*x^m*P(x, n - m), n^(m/2)*P(x, n - m)], {m, 1, k}].at n=48A138094
• Numbers k such that sigma(k) = psi(k) + phi(k).at n=17A389478