22684

Appears in sequences

• Numbers k such that the number of divisors of k equals the number of anti-divisors of k.at n=13A073694
• Triangular matrix, read by rows, that satisfies: T(n,k) = [T^2](n-1,k) when n>k>=0, with T(n,n) = (n+1).at n=22A102086
• Column 1 of triangular matrix A102086, which shifts upward to exclude the main diagonal under matrix square.at n=6A102087
• Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,0 4,0 5,0 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155278
• Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,0 4,0 5,0 6,0 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155330
• Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155386
• Numbers n such that n!8-1 is prime.at n=59A204662
• Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=6A299816
• Number of n X 7 0..1 arrays with every element equal to 0, 2, 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=2A299820
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=38A299821
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=42A299821
• a(n) = prime(n)*(prime(n-1) + prime(n+1)).at n=26A357679
• a(n) = (n-1)!/2^floor((n-1)/2) + floor((n-1)/2).at n=9A372256