91371

Appears in sequences

• Structured pentagonal icositetrahedral numbers (vertex structure 10).at n=20A100168
• Triangle read by rows: T(0,0)=1; for n >= 1 T(n,k) is the coefficient of x^k in the monic characteristic polynomial of the tridiagonal n X n matrix with main diagonal 5,5,5,... and sub- and superdiagonals 1,1,1,... (0 <= k <= n).at n=29A123967
• Triangle of coefficients of Chebyshev's S(n,x+5) polynomials (exponents of x in increasing order).at n=29A207824
• G.f. satisfies: A(x) = (1 + x*(3-x)*A(x)) * (1 + x^2*A(x)).at n=9A216454
• Numbers k such that k^2 +- k +- 1 is prime for all four possibilities.at n=20A236056
• Number of vertices in an equilateral triangle "frame" of size n (see Comments in A328526 for definition).at n=21A333031