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A361491
Expansion of x*(1+38*x+x^2)/((1-x)*(x^2-34*x+1)).
1
1, 73, 2521, 85681, 2910673, 98877241, 3358915561, 114104251873, 3876185648161, 131676207785641, 4473114879063673, 151954229680379281, 5161970694253831921, 175355049374949906073, 5956909708054042974601, 202359575024462511230401, 6874268641123671338859073, 233522774223180363009978121
OFFSET
1,2
COMMENTS
Indices i of Tetrahedral Numbers T(i) such that T(i)*T(2*i) is a perfect square. [Ulas]
LINKS
FORMULA
a(n) = 35*a(n-1) -35*a(n-2) +a(n-3).
a(n) = 17*a(n-1)+36*A046176(n-1)+20. [Ulas]
4*a(n) = -5+9*(A029547(n)-33*A029547(n-1)).
MATHEMATICA
LinearRecurrence[{35, -35, 1}, {1, 73, 2521}, 20] (* Paolo Xausa, Jan 18 2024 *)
CROSSREFS
Cf. A046176.
Sequence in context: A217286 A282784 A332912 * A017789 A017736 A221826
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Mar 14 2023
STATUS
approved