OFFSET
2,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 2..1000
FORMULA
a(n) = Sum_{k=1..n-1} A120073(n,k), for n >= 2.
MATHEMATICA
A120075[n_]:= Sum[Denominator[1/k^2 -1/n^2], {k, n-1}];
Table[A120075[n], {n, 2, 50}] (* G. C. Greubel, Apr 24 2023 *)
PROG
(Magma)
A120073:= func< n, k | Denominator(1/k^2 - 1/n^2) >;
[(&+[A120073(n, k): k in [1..n-1]]): n in [2..50]]; // G. C. Greubel, Apr 24 2023
(SageMath)
def A120073(n, k): return denominator(1/k^2 - 1/n^2)
[sum(A120073(n, k) for k in range(1, n)) for n in range(2, 51)] # G. C. Greubel, Apr 24 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Jul 20 2006
STATUS
approved