OFFSET
1,2
COMMENTS
Indices i of Tetrahedral Numbers T(i) such that T(i)*T(2*i) is a perfect square. [Ulas]
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..500
Maciej Ulas, On certain diophantine equations related to triangular and tetrahedral numbers, arXiv:0811.2477 [math.NT] (2008) , u_n in Theorem 5.6.
Index entries for linear recurrences with constant coefficients, signature (35,-35,1).
FORMULA
MATHEMATICA
LinearRecurrence[{35, -35, 1}, {1, 73, 2521}, 20] (* Paolo Xausa, Jan 18 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Mar 14 2023
STATUS
approved