253992

Appears in sequences

• Expansion of g.f. x*(1 +30*x +49*x^2 -71*x^3 -116*x^4)/((1+2*x)*(1-2*x^2) *(1-2*x-4*x^2)).at n=9A121960
• a(n) = 576*n^2 - 24.at n=20A158636
• Place n points in general position on each side of an equilateral triangle, and join every pair of the 3*n+3 boundary points by a chord; sequence gives number of vertices in the resulting planar graph.at n=18A367117