21793

Appears in sequences

• Number of different words that can be formed from an n X n grid of letters, reading horizontally, vertically or diagonally.at n=18A034720
• Expansion of (1-x)^(-1)/(1-x-2*x^2+x^3).at n=16A077865
• Denominator of Product_{ 2 <= p < 2*n } (2*n - p)/p.at n=22A084763
• Expansion of 1/sqrt(1 - 6x + 17x^2).at n=8A098339
• The Wiener index of a chain of n triangles (i.e., joined like VVV..VV; here V is a triangle!).at n=30A143941
• Products of three consecutive primes of the form 6n+1 (see A002476).at n=2A154728
• a(n) = 21*n^2 - 33*n + 13.at n=32A289134
• a(n) = denominator(b(n)), where b(0) = b(1) = 1 and b(n) = n*b(n-1)/b(n-2) for n >= 1.at n=40A329813
• Numerators of minimal squared radii of circular disks covering a record number of lattice points of the hexagonal lattice, when the centers of the circles are chosen to maximize the number of covered lattice points.at n=24A346784