23809

Appears in sequences

• a(n) = 12*a(n-1) + 7*a(n-2).at n=5A015611
• Expansion of 1/((1-x)*(1-2*x)*(1-6*x)*(1-9*x)).at n=4A021194
• Numbers k such that Sum_{i=1..k} i^6 divides Product_{i=1..k} i^6.at n=21A166606
• n for which A079277(n) + phi(n) < n.at n=18A208815
• a(n) = (16/3)*(n+1)*n*(n-1) + 8*n^2 + 1.at n=15A212668
• Place n equally spaced points on each side of an equilateral triangle, and join each of these points by a chord to the 2*n new points on the other two sides: sequence gives number of interior vertices in the resulting planar graph.at n=11A366484