18054

Appears in sequences

• Apply partial sum operator thrice to primes.at n=18A014150
• Number of similarity classes of triangles which can be drawn using the lattice points in an n X n grid for vertices.at n=19A028492
• Numbers k such that prime(k+3)-(k+3)*tau(k+3) = prime(k-3)-(k-3)*tau(k-3) where tau(k) = A000005(k) is the number of divisors of k.at n=38A067355
• Triangle read by rows, based on a simple Fibonacci recursion rule.at n=49A111669
• Number of strings of numbers x(i=1..6) in 0..n with sum i*x(i)^2 equal to n*36.at n=16A184445
• Number of hybrid 8-ary trees with n internal nodes.at n=4A245051
• a(n) = (2*n+23)*n*(n-1), a coefficient appearing in the formula a(n)*Pi/324+n+1 giving the average number of regions into which n random planes divide the cube.at n=18A248598
• Number of length 3+1 0..n arrays with the sum of the maximum of each adjacent pair multiplied by some arrangement of +-1 equal to zero.at n=32A250647
• Number of nXnXn triangular 0..4 arrays with new values introduced in sequential zero-upwards order and exactly one upright 2x2x2 triangle having values all equal.at n=3A271336
• T(n,k)=Number of nXnXn triangular 0..k arrays with new values introduced in sequential zero-upwards order and exactly one upright 2x2x2 triangle having values all equal.at n=24A271339
• Coefficients in the expansion of 1/([r]-[2r]x+[3r]x^2-...); [ ]=floor, r=8/5.at n=17A289260
• Number of nX5 0..1 arrays with every element unequal to 0, 1, 3, 4, 6 or 7 king-move adjacent elements, with upper left element zero.at n=7A306126
• a(n) is the n-th term of the n-fold self-convolution of the twice left-shifted tribonacci sequence (A000073).at n=7A341266
• G.f. satisfies A(x) = 1 + x*A(x) + x^5*A(x)^5.at n=15A364522