38556

Appears in sequences

• Numbers k such that the three second-degree cyclotomic polynomials x^2 + 1, x^2 - x + 1 and x^2 + x + 1 are simultaneously prime when evaluated at x=k.at n=22A087277
• Number of permutations of length n with exactly 2 occurrences of the pattern 2-13.at n=8A094218
• Triangle read by rows: T(n,k) is number of hex trees with n edges and k nonroot nodes of outdegree 2.at n=29A126183
• Triangle, read by rows, where the g.f. of column k, C_k(x), is defined by the recursion: C_k(x) = ( 1 + Sum_{n>=1} x^n*C_{n-1+k}(x) )^(k+1).at n=49A127082
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 1), (0, 1, 0), (1, 0, -1), (1, 0, 1)}.at n=8A150560
• Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant in {0,1,...,n}.at n=26A209995
• Triangle read by rows: T(n,k) (n>=0, 0<=k<=A002620(n-1)) is the number of permutations of [n] with k nestings.at n=45A263776
• a(n) = 6*n*(9*n-5).at n=27A277984
• Factor balanced numbers. See Comments for definition.at n=19A343153
• Triangular array T(n, k) read by rows: polynomials for the series expansion of the iterated function F^{t}(x) = Sum_{n>=0} (1/x)^(2*n-1)*P_n(t)/n! with F^{1}(x) = (x + sqrt(x^2 + 4))/2 and F^{2}(x) = F^{1}(F^{1}(x)). Row n of the triangle give the coefficients of the polynomial P_n(t).at n=30A390822