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 A088899 T(n,k) = number of ordered pairs of integers (x,y) with x^2/n^2 + y^2/k^2 = 1, 1<=k<=n; triangular array, read by rows. 2
 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 12, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 12, 4, 4, 4, 4, 12, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 12, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS T(n,k) = number of lattice points on the circumference of an ellipse with semimajor axis = n, semiminor axis = k and center = (0,0). a(n) = A088897(n) - A088898(n); T(n,n) = A046109(n). LINKS Eric Weisstein's World of Mathematics, Ellipse CROSSREFS Sequence in context: A032564 A141248 A273339 * A258199 A066014 A080678 Adjacent sequences:  A088896 A088897 A088898 * A088900 A088901 A088902 KEYWORD nonn,tabl AUTHOR Reinhard Zumkeller, Oct 21 2003 STATUS approved

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