43513

Appears in sequences

• Triangle T(n,k), n >= 1, giving number of prime unoriented alternating links with n crossings and k components.at n=88A059739
• Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,2}.at n=33A079966
• Expansion of (1-x+sqrt(1-2x+5x^2))/(2(1-x)^2).at n=20A134920
• Number of intersections of diagonals in the interior and exterior of a regular n-gon.at n=25A211383
• Centered square numbers (A001844) which are also centered heptagonal numbers (A069099).at n=2A253599
• Centered heptagonal numbers which are semiprime.at n=41A381960