OFFSET
2,1
LINKS
G. C. Greubel, Rows n = 2..50 of the triangle, flattened
Wofdieter Lang, First ten rows, rationals and more.
FORMULA
a(m,n) = denominator(r(m,n)) with r(m,n) = 1/n^2 - 1/m^2, m>=2, n=1..m-1.
EXAMPLE
For the rational triangle see W. Lang link.
Denominator triangle begins as:
4;
9, 36;
16, 16, 144;
25, 100, 225, 400;
36, 9, 12, 144, 900;
49, 196, 441, 784, 1225, 1764;
64, 64, 576, 64, 1600, 576, 3136;
81, 324, 81, 1296, 2025, 324, 3969, 5184;
100, 25, 900, 400, 100, 225, 4900, 1600, 8100;
MATHEMATICA
Table[(1/n^2 - 1/m^2)//Denominator, {m, 2, 15}, {n, m-1}]//Flatten (* Jean-François Alcover, Sep 16 2013 *)
PROG
(Magma) [Denominator(1/k^2 - 1/n^2): k in [1..n-1], n in [2..18]]; // G. C. Greubel, Apr 24 2023
(SageMath)
def A120073(n, k): return denominator(1/k^2 - 1/n^2)
flatten([[A120073(n, k) for k in range(1, n)] for n in range(2, 19)]) # G. C. Greubel, Apr 24 2023
CROSSREFS
KEYWORD
AUTHOR
Wolfdieter Lang, Jul 20 2006
STATUS
approved