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A101152
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Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+569)^2 = y^2.
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6
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0, 111, 1260, 1707, 2280, 8791, 11380, 14707, 52624, 67711, 87100, 308091, 396024, 509031, 1797060, 2309571, 2968224, 10475407, 13462540, 17301451, 61056520, 78466807, 100841620, 355864851, 457339440, 587749407, 2074133724, 2665570971
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OFFSET
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1,2
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COMMENTS
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Also values x of Pythagorean triples (x, x+569, y).
Corresponding values y of solutions (x, y) are in A160090.
lim_{n -> infinity} a(n)/a(n-3) = 3+2*sqrt(2).
lim_{n -> infinity} a(n)/a(n-1) = (587+102*sqrt(2))/569 for n mod 3 = {1, 2}.
lim_{n -> infinity} a(n)/a(n-1) = (617139+371510*sqrt(2))/569^2 for n mod 3 = 0.
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LINKS
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G. C. Greubel, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,0,6,-6,0,-1,1).
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FORMULA
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a(n) = 6*a(n-3) - a(n-6) + 1138 for n > 6; a(1)=0, a(2)=111, a(3)=1260, a(4)=1707, a(5)=2280, a(6)=8791.
G.f.: x*(111 +1149*x +447*x^2 -93*x^3 -383*x^4 -93*x^5)/((1-x)*(1-6*x^3 +x^6)).
a(3*k+1) = 569*A001652(k) for k >= 0.
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MATHEMATICA
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LinearRecurrence[{1, 0, 6, -6, 0, -1, 1}, {0, 111, 1260, 1707, 2280, 8791, 11380}, 50] (* G. C. Greubel, Apr 21 2018 *)
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PROG
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(PARI) {forstep(n=0, 10000000, [3, 1], if(issquare(2*n^2+1138*n+323761), print1(n, ", ")))}
(PARI) x='x+O('x^30); concat([0], Vec(x*(111 +1149*x +447*x^2 -93*x^3 -383*x^4 -93*x^5)/((1-x)*(1-6*x^3 +x^6)))) \\ G. C. Greubel, Apr 21 2018
(Magma) I:=[0, 111, 1260, 1707, 2280, 8791, 11380]; [n le 7 select I[n] else Self(n-1) +6*Self(n-3) -6*Self(n-4) -Self(n-6) +Self(n-7): n in [1..30]]; // G. C. Greubel, Apr 21 2018
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CROSSREFS
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Cf. A160090, A129298, A001652, A156035 (decimal expansion of 3+2*sqrt(2)), A160091 (decimal expansion of (587+102*sqrt(2))/569), A160092 (decimal expansion of (617139+371510*sqrt(2))/569^2).
Sequence in context: A302475 A303256 A137465 * A250145 A075859 A264466
Adjacent sequences: A101149 A101150 A101151 * A101153 A101154 A101155
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KEYWORD
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nonn,easy
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AUTHOR
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Mohamed Bouhamida, Jun 03 2007
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EXTENSIONS
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Edited and two terms added by Klaus Brockhaus, May 04 2009
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STATUS
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approved
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