67620

Appears in sequences

• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 26.at n=19A031704
• In the interior of a regular 2n-gon with all diagonals drawn, the number of points where exactly three diagonals intersect.at n=40A101363
• Numbers k such that k divides 1 + Sum_{j=1..k} prime(j)^2 = 1 + A024450(k).at n=25A128166
• a(n) = 676*n^2 + 2*n.at n=9A158385
• a(n) = 400*n^2 + 20.at n=13A158601
• A diagonal in the array A158825 of coefficients of successive iterations of x*C(x), where C(x) is the Catalan function (A000108).at n=5A158834
• Triangle T such that row n of T^n = row n of (I+D)^(n^2) where D is the lower diagonal matrix: D(n+1,n)=n+1, and I is the identity matrix.at n=32A173210
• a(n) = 169*n^2 + n.at n=19A173275
• Number of 0..n arrays x(0..5) of 6 elements with zero 4th differences.at n=34A200084
• Triangle read by rows: T(n,k) is the number of stretching pairs in all permutations in S_{n,k} (=set of permutations in S_n with k cycles) (n >= 3; 1 <= k <= n-2).at n=33A216118
• Number of distinct topologies on an n-set that have exactly 7 open sets.at n=7A281775
• Real parts of the recursive sequence a(n+2) = Sum_{k=0..n} binomial(n,k)*a(k)*a(n+1-k), with a(0)=1, a(1)=2i.at n=9A289086