90940

Appears in sequences

• Triangular array E(n,k) counting not necessarily connected k-regular simple graphs on n vertices with girth at least 5.at n=76A185305
• Irregular triangle E(n,g) counting not necessarily connected 3-regular simple graphs on 2n vertices with girth at least g.at n=29A185330
• Number of not necessarily connected 3-regular simple graphs on 2n vertices with girth at least 5.at n=11A185335
• a(n) = n^4/2-5*n^3/2+21*n-30.at n=20A217530
• Number of prime numbers of the form k^2 + k + 41 below 10^n.at n=10A319906