23168

Appears in sequences

• Expansion of tan(tan(x))*x.at n=4A009700
• Pisot sequence T(4,6), a(n) = floor(a(n-1)^2/a(n-2)).at n=32A020747
• Pisot sequence T(6,9), a(n) = floor(a(n-1)^2/a(n-2)).at n=31A020751
• Numbers k that divide the (left) concatenation of all numbers <= k written in base 13 (most significant digit on left).at n=24A029482
• a(n) = sigma[k](n) - phi(n)^k - d(n)^k for k=3.at n=27A079539
• a(n) = 2*a(n-1) + 2*a(n-2) for n > 1; a(0)=2, a(1)=2.at n=10A080040
• Values of s in Wolfram's iteration for sqrt(2).at n=13A095804
• a(n) equals the (n*(n+1)/2)-th partial sum of the self-convolution 4th power of A010054, which has the g.f.: Sum_{k>=0} x^(k*(k+1)/2).at n=16A109415
• Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,0 3,1 3,2 4,2 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155321
• a(n) = 8*a(n-1) - 8*a(n-2) for n > 1; a(0) = 1, a(1) = 10.at n=5A164546
• Number of permutations of 1..n avoiding adjacent step pattern up, down, up, down.at n=8A177520
• Triangle of coefficients of polynomials v(n,x) jointly generated with A208917; see the Formula section.at n=52A208918
• Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 2 X n array.at n=19A220045
• Number T(n,k) of permutations of [n] with exactly k (possibly overlapping) occurrences of the consecutive step pattern up, down, up, down; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-3)/2)), read by rows.at n=12A230797
• Number of length n+2 0..4 arrays with no pair in any consecutive three terms totalling exactly 4.at n=5A245991
• T(n,k)=Number of length n+2 0..k arrays with no pair in any consecutive three terms totalling exactly k.at n=41A245995
• Number of length 6+2 0..n arrays with no pair in any consecutive three terms totalling exactly n.at n=3A246001
• Number of (n+2) X (4+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically.at n=9A253506
• One half of the y members of the positive proper solutions (x = x2(n), y = y2(n)) of the second class for the Pell equation x^2 - 2*y^2 = +7^2.at n=5A275796
• Values of m such that m^2 + 6 is a triangular number (A000217).at n=17A276600