21571

Appears in sequences

• Generalized Fibonacci numbers: a(n) = a(n-1) + 10*a(n-2).at n=8A015446
• Number of 5-element families of an n-element set such that every 3 members of the family have a nonempty intersection.at n=5A051364
• Starting positions of strings of three 7's in the decimal expansion of Pi.at n=22A083631
• First subdiagonal of generalized Fibonacci array A083856.at n=9A083860
• Number of fixed points of mirroring operation on solid partitions.at n=20A096573
• Number of ways to label the vertices of the octahedron (or faces of the cube) with nonnegative integers summing to n, where labelings that differ only by rotation or reflection are considered the same.at n=37A097513
• a(n) = ((5+sqrt(2))*(1+sqrt(2))^n + (5-sqrt(2))*(1-sqrt(2))^n)/2.at n=10A162268
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 355", based on the 5-celled von Neumann neighborhood.at n=31A271399
• Numbers k for which rank of the elliptic curve y^2=x^3-k*x is 4.at n=16A309034
• Numbers whose binary indices have (1) prime indices covering an initial interval and (2) squarefree product.at n=44A371293