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A370188
a(n) = sqrt((A114052(n)^2 - 1)/27)/5.
1
0, 1, 52, 2703, 140504, 7303505, 379641756, 19734067807, 1025791884208, 53321443911009, 2771689291488260, 144074521713478511, 7489103439809394312, 389289304348375025713, 20235554722675691942764, 1051859556274787605998015, 54676461371566279819954016, 2842124131765171763031610817
OFFSET
0,3
COMMENTS
5*a(n) are the y-values in solutions to x^2 - 27*y^2 = 1.
FORMULA
G.f.: x/(1 - 52*x + x^2).
EXAMPLE
a(2) = 52: A114052(2) = 1351; 1351^2 - 27*(5*52)^2 = 1825201 - 1825200 = 1.
MATHEMATICA
LinearRecurrence[{52, -1}, {0, 1}, 18]
CROSSREFS
Cf. A114052.
Sequence in context: A004296 A097837 A247628 * A262272 A189908 A189902
KEYWORD
nonn,easy
AUTHOR
Hugo Pfoertner, Feb 11 2024
STATUS
approved