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A281239
Solutions x to the negative Pell equation y^2 = 72*x^2 - 83232 with x,y >= 0.
3
34, 38, 66, 102, 162, 358, 578, 934, 2082, 3366, 5442, 12134, 19618, 31718, 70722, 114342, 184866, 412198, 666434, 1077478, 2402466, 3884262, 6280002, 14002598, 22639138, 36602534, 81613122, 131950566, 213335202, 475676134, 769064258, 1243408678, 2772443682
OFFSET
1,1
COMMENTS
The corresponding values of y are in A281240.
LINKS
S. Vidhyalakshmi, V. Krithika, K. Agalya, On The Negative Pell Equation  y^2 = 72*x^2 - 8, International Journal of Emerging Technologies in Engineering Research (IJETER), Volume 4, Issue 2, February (2016).
FORMULA
a(n) = 6*a(n-3) - a(n-6) for n>6.
G.f.: 2*x*(17 + 19*x + 33*x^2 - 51*x^3 - 33*x^4 - 19*x^5) / (1 - 6*x^3 + x^6).
EXAMPLE
38 is in the sequence because (x, y) = (38,144) is a solution to y^2 = 72*x^2 - 83232.
PROG
(PARI) Vec(2*x*(17 + 19*x + 33*x^2 - 51*x^3 - 33*x^4 - 19*x^5) / (1 - 6*x^3 + x^6) + O(x^40))
CROSSREFS
Cf. A281240.
Equals (1/4)* A281241.
Sequence in context: A345510 A300155 A250738 * A295750 A141699 A296096
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Jan 19 2017
STATUS
approved