131418

Appears in sequences

• Coordination sequence for 4-dimensional face-centered cubic orthogonal lattice.at n=27A008529
• Dirichlet convolution of b_n = 2^(n-1) with phi(n).at n=17A034738
• a(n) = Sum_{d|n} sigma_[n/d](d), where sigma_[k](n) is the sum of the k-th powers of the divisors of n.at n=33A348398
• Expansion of 1/sqrt(1 - 2*x + 3*x^2 + 2*x^3 + x^4).at n=23A375021