290970

Appears in sequences

• Numbers k that can be expressed as k = w + x = y*z with w*x = y^2 + z^2 where w, x, y, and z are all positive integers.at n=29A057373
• Number of permutations of length n without increasing or decreasing modular 3-sequences.at n=6A165963
• Number of permutations of length n with no consecutive triples i,i+2,i+4 (mod n) or i,i-2,i-4 (mod n).at n=9A174077
• Triangle read by rows: T(n,k) is the number of permutations of k elements from [1..n] with longest consecutive chain size less than 3, when 1 and n are considered to be consecutive.at n=54A340107
• G.f. A(x) satisfies A(x) = 1 + x^4 * (A(x) / (1 - x))^2.at n=25A361229