23075

Appears in sequences

• Coefficient of x^4 in expansion of (1+x+x^2)^n.at n=24A005712
• Numbers n such that sigma(phi(n))/sigma(n) = 2.at n=34A067382
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, -1, 1), (-1, 0, -1), (1, 0, -1), (1, 1, 0)}.at n=10A148581
• Number of binary words of length n containing no subword 01101.at n=15A209888
• Number of different chromatic polynomials of a simple graph with n nodes.at n=8A229048
• a(n) = Sum_{k=0..n} binomial(n,k) * (2^k + 3^k)^(n-k) * 3^(k^2).at n=3A245105
• Number T(n,k) of binary words of length n containing exactly k (possibly overlapping) occurrences of the subword 01101; triangle T(n,k), n>=0, k=0..max(0,floor((n-2)/3)), read by rows.at n=37A277751
• a(n) = trinomial(2*n, 4) = (1/6)*n*(2*n - 1)*(2*n^2 + 7*n - 3).at n=13A302710