|
|
A088898
|
|
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
|
|
|
1, 3, 9, 5, 15, 25, 7, 21, 31, 45, 9, 27, 41, 59, 69, 11, 33, 51, 69, 87, 109, 13, 39, 61, 83, 105, 127, 145, 15, 41, 67, 93, 119, 141, 171, 193, 17, 47, 77, 103, 137, 159, 193, 219, 249, 19, 53, 87, 117, 147, 181, 215, 241, 275, 305, 21, 59, 97, 131, 165, 203
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
T(n,k) = number of inner lattice points of an ellipse with semimajor axis = n, semiminor axis = k and center = (0,0).
|
|
LINKS
|
Eric Weisstein's World of Mathematics, Ellipse
|
|
MATHEMATICA
|
T[1, 1] = 1;
T[n_, k_] := Reduce[x^2/n^2 + y^2/k^2 < 1, {x, y}, Integers] // Length;
|
|
CROSSREFS
|
|
|
KEYWORD
|
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|