39606

Appears in sequences

• Number of forests of different trees.at n=16A035055
• a(n) = Lucas(4*n+2) + 3, or Lucas(2*n)*Lucas(2*n+2).at n=5A081077
• Numbers k such that 6*R_k + 1 is a prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=29A096507
• Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 2 which is symmetric after a rotation by 180 degrees.at n=9A123819
• Partial sums of A140091.at n=41A267370
• a(n) = L(n)^2 - 5*(-1)^n = L(n+1)*L(n-1), where L = A000032.at n=11A292696
• Numbers that can be written as the sum of four or more consecutive squares in more than one way.at n=31A307937
• a(n) is the smallest number which can be represented as the sum of n distinct centered n-gonal numbers in exactly n ways, or -1 if no such number exists.at n=18A352975
• The number of vertices formed when every pair of n points, placed at the vertices of a regular n-gon, are connected by a circle and where the points lie at the ends of the circle's diameter.at n=21A358746
• a(n) = Lucas(n) + 3.at n=21A366506