-1949

Appears in sequences

• Partition function coefficients for square lattice spin 1 Ising model.at n=20A010107
• Triangle read by rows giving the coefficients of general sum formulas of n-th Subfactorial numbers (A000166). The k-th row (k>=1) contains T(i,k) for i=1 to 2*k-1, where T(i,k) satisfies Subf(n) = Sum_{k=1..n} Sum_{i=1..2*k-1} T(i,k) * C(n-k,i-1) * n^(n-k).at n=26A101560
• G.f. A(x) satisfies: A(x)^2 = A(x^2) + 4*x.at n=10A107087
• G.f. A(x) satisfies: A(x) = A(x^2)^(1/2) + 4*x.at n=20A107088
• a(1) = 1; a(2) = 1; a(3) = 1; a(4) = 1; a(5) = 1; a(n) = a(n-1)+4a(n-2)-3a(n-3)-3a(n-4)+a(n-5) for n >= 6.at n=15A122608
• G.f. A(x) satisfies 0 = f(A(x), A(x^2)) where f(u, v) = u * (u - 2) - (v + 2).at n=20A193527