A145308 Numbers n such that there exists x in N : (x+1)^3-x^3=79*n^2.

19, 8669719, 3956010119119, 1805135329365568219, 823686861056211499347019, 375849962071866284245677895519, 171501089392493042372815103581763719, 78256290091597510258728411110320270611619, 35708501681204626036685798404088545017041209219

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..180

Index entries for linear recurrences with constant coefficients, signature (456302,-1).

Formula

a(n+2) = 456302*a(n+1)-a(n).

G.f.: -19*x*(x-1) / (x^2-456302*x+1). - Colin Barker, Oct 19 2014

Example

a(1)=19 because the first relation is : 98^3-97^3=79*19^2.

Mathematica

CoefficientList[Series[19 (1 - x)/(x^2 - 456302 x + 1), {x, 0, 20}], x] (* Vincenzo Librandi, Oct 19 2014 *)
LinearRecurrence[{456302, -1}, {19, 8669719}, 10] (* Harvey P. Dale, Dec 10 2015 *)

Prog

(PARI) Vec(-19*x*(x-1) / (x^2-456302*x+1) + O(x^20)) \\ Colin Barker, Oct 19 2014
(Magma) I:=[19, 8669719]; [n le 2 select I[n] else 456302*Self(n-1)-Self(n-2): n in [1..10]]; // Vincenzo Librandi, Oct 19 2014

Crossrefs

Sequence in context: A172875 A172839 A177920 * A087515 A038028 A013890

Adjacent sequences: A145305 A145306 A145307 * A145309 A145310 A145311

Keyword

easy,nonn

Author

Richard Choulet, Oct 06 2008

Status

approved