21449

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 59.at n=32A020398
• Number of increasing sequences of n integers x(1),...,x(n) with values in 1..5*n such that x(j) divides x(k) iff j divides k.at n=19A180382
• Sum of the diagonal entries of the table of marks of the alternating group.at n=7A218920
• Nonprime terms in A210494.at n=16A230214
• Number of dominating sets in the stacked prism graph C_3 X P_n.at n=4A285880
• Array read by antidiagonals: T(m,n) = number of dominating sets in the stacked prism graph C_m X P_n.at n=23A286514
• Expansion of Product_{k>=1} 1/((1 - x^k) * (1 - x^(2*k)) * (1 - x^(3*k))).at n=24A327042
• a(n) is the number of 4 element sets of integer sided trapezoids with distinct areas and base angles that are 60 degrees, which fill an equilateral triangular grid of side n units.at n=47A389518