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A227077
y solutions to the Diophantine equation 2*x^2*(x^2 - 1) = 3*(y^2 - 1)
1
1, 3, 7, 29, 6761
OFFSET
0,2
COMMENTS
Also solutions to (2*x^2 - 1)^2 = 6*y^2 - 5 as outlined in A180445, which gives the x solutions to this equation {1, 2, 3, 6, 91}.
(sqrt(2)*sqrt(sqrt(6*a(n)^2 - 5) + 1) - 1)^2 = A038198(n)^2 gives the Ramanujan-Nagell squares listed in A227078.
LINKS
MATHEMATICA
Select[Table[Sqrt[3-2x^2+2x^4]/Sqrt[3], {x, 0, 100}], IntegerQ]//Union (* Harvey P. Dale, Aug 11 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Raphie Frank, Jun 30 2013
STATUS
approved