A130005 Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+577)^2 = y^2.

0, 35, 1568, 1731, 1908, 10595, 11540, 12567, 63156, 68663, 74648, 369495, 401592, 436475, 2154968, 2342043, 2545356, 12561467, 13651820, 14836815, 73214988, 79570031, 86476688, 426729615, 463769520, 504024467, 2487163856, 2703048243

Offset

1,2

Comments

Also values x of Pythagorean triples (x, x+577, y).

Corresponding values y of solutions (x, y) are in A159626.

For the generic case x^2+(x+p)^2 = y^2 with p = 2*m^2-1 a (prime) number in A066436 see A118673 or A129836.

lim_{n -> infinity} a(n)/a(n-3) = 3+2*sqrt(2).

lim_{n -> infinity} a(n)/a(n-1) = (579+34*sqrt(2))/577 for n mod 3 = {1, 2}.

lim_{n -> infinity} a(n)/a(n-1) = (855171+556990*sqrt(2))/577^2 for n mod 3 = 0.

Links

Table of n, a(n) for n=1..28.

Index entries for linear recurrences with constant coefficients, signature (1,0,6,-6,0,-1,1).

Formula

a(n) = 6*a(n-3)-a(n-6)+1154 for n > 6; a(1)=0, a(2)=35, a(3)=1568, a(4)=1731, a(5)=1908, a(6)=10595.

G.f.: x*(35+1533*x+163*x^2-33*x^3-511*x^4-33*x^5) / ((1-x)*(1-6*x^3+x^6)).

a(3*k+1) = 577*A001652(k) for k >= 0.

Mathematica

LinearRecurrence[{1, 0, 6, -6, 0, -1, 1}, {0, 35, 1568, 1731, 1908, 10595, 11540}, 30] (* Harvey P. Dale, May 27 2018 *)

Prog

(PARI) {forstep(n=0, 500000000, [3, 1], if(issquare(2*n^2+1154*n+332929), print1(n, ", ")))}

Crossrefs

Cf. A159626, A066436, A118673, A118674, A129836, A001652, A156035 (decimal expansion of 3+2*sqrt(2)), A159627 (decimal expansion of (579+34*sqrt(2))/577), A159628 (decimal expansion of (855171+556990*sqrt(2))/577^2).

Sequence in context: A249885 A135923 A180883 * A199362 A187364 A183417

Adjacent sequences: A130002 A130003 A130004 * A130006 A130007 A130008

Keyword

nonn,easy

Author

Mohamed Bouhamida, Jun 15 2007

Extensions

Edited and two terms added by Klaus Brockhaus, Apr 21 2009

Status

approved