A201226 Values y for infinite sequence x^3-y^2 = d with decreasing coefficient r=sqrt(x)/d which tend to 1/(1350*sqrt(5))or infinity family of solutions Mordell curve with extension sqrt(5).

476425, 3499913125, 20477027135825, 118398467411226125, 684132799477496491225, 3952927722012200964659125, 22840018438688230285823134625, 131969623469705492999569294932125, 762520461852550579069844280191898025

Offset

1,1

Comments

For x values see A201225.

For d values see A201227.

Links

Table of n, a(n) for n=1..9.

Index entries for linear recurrences with constant coefficients, signature (6118, -1970319, 33501524, -1970319, 6118, -1).

Formula

g.f.: -((25*(-19057-23405799*z-130714666*z^2+9631442*z^3-

30549*z^4+5*z^5))/((1-5778*z+z^2)*(1-322*z+z^2)*(1-18*z+z^2))).

a(n) =6118*a(n-1) - 1970319*a(n-2) + 33501524*a(n-3) - 1970319*a(n-4) + 6118*(a(n-5) - a(n-6).

Mathematica

LinearRecurrence[{6118, -1970319, 33501524, -1970319, 6118, -1}, {476425, 3499913125, 20477027135825, 118398467411226125, 684132799477496491225, 3952927722012200964659125}, 20] (* Harvey P. Dale, Jun 12 2013 *)

Crossrefs

Cf. A201225, A201227.

Sequence in context: A219996 A183659 A213994 * A244628 A290050 A244086

Adjacent sequences: A201223 A201224 A201225 * A201227 A201228 A201229

Keyword

nonn

Author

Artur Jasinski, Nov 28 2011

Status

approved