31845

Appears in sequences

• Number of positive integers <= 2^n of the form 3*x^2 + 4*y^2.at n=18A000049
• Numbers of the form m = p1 * p2 * p3 * p4 where for each d|m we have (d+m/d)/2 prime and p1 < p2 < p3 < p4 each prime.at n=6A128285
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2<x^2+y^2.at n=35A211635
• Number of ordered pairs of endofunctions f,g on a set of n elements satisfying f(f(x)) = g(g(g(x))).at n=5A235325
• a(n) is the number of isosceles trapezoids in a triangular grid of side length n.at n=19A389363