30160

Appears in sequences

• Rounded volume of a regular icosahedron with edge length n.at n=24A071402
• Even numbers k such that the central binomial coefficient A000984(k, k/2) is divisible by k^2.at n=19A080395
• Positive integers n such that n^2 = (x^4 - y^4)*(z^4 - t^4) where the pairs of integers (x,y) and (z,t) are not proportional.at n=23A147854
• Positive integers n such that n^2 = (x^4 - y^4)*(z^4 - t^4) where x>y and z>t are distinct pairs of integers with gcd(x,y)=gcd(z,t)=1.at n=9A147856
• The first n-fold (at least) intrinsically 2-palindromic number (in base ten).at n=40A171701
• Number of ways to place 2 nonattacking bishops on an n X n board.at n=15A172123
• Number of n X n 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=4A208694
• Number of nX5 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=4A208695
• T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=40A208698
• Number of 5Xn 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=4A208700
• Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having two, three, four or five distinct values for every i,j,k<=n.at n=10A211571
• The denominators of Zagier's modification of the Bernoulli numbers.at n=27A216923
• Number of n X 2 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero.at n=9A230904
• Expansion of x^6*(1 + x^3)/(1 - 4*x + 5*x^2 - x^3 - 2*x^4 + x^6 + x^7 - 2*x^8 + x^9).at n=14A290989
• a(n) = 36*n^2 - 4*n (n>=1).at n=28A304380
• a(n) = n*(n + 1)*(7*n + 5)/6.at n=29A304993
• Numbers k such that e(k) > 1 and k == e(k) (mod lambda(k)), where e(k) = A051903(k) is the maximal exponent in prime factorization of k.at n=20A327295
• Table read by rows: T(n,k) = number of k-gons, k >= 3, formed inside a square with edge length 1 by the straight line segments mutually connecting all vertices and points that divide the sides into segments with lengths equal to the Farey series of order n = A006842(n,m)/A006843(n,m), m = 1..A005728(n).at n=30A358889
• a(n) = Sum_{k=0..floor(n/2)} 2^k * 3^(n-2*k) * binomial(k,n-2*k)^2.at n=12A387478