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Numbers x such that there exists n in N : (x+1)^3-x^3=19*n^2.
3

%I #15 Jan 06 2024 00:57:48

%S 2,757,228762,69085517,20863597522,6300737366277,1902801821018282,

%T 574639849210155037,173539331659645803042,52408303521363822363797,

%U 15827134124120214708063802,4779742097180783478012904557,1443466286214472490145189112562

%N Numbers x such that there exists n in N : (x+1)^3-x^3=19*n^2.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (303,-303,1).

%F a(n+2) = 302*a(n+1)-a(n)+150.

%F G.f.: x*(-2-151*x+3*x^2) / ( (x-1)*(x^2-302*x+1) ). - _R. J. Mathar_, Nov 27 2011

%e a(1)=2 because 3^3-2^3=19*1.

%t CoefficientList[Series[(-2 - 151*x + 3*x^2)/((x - 1)*(x^2 - 302*x + 1)), {x, 0, 15}], x] (* _Wesley Ivan Hurt_, Sep 04 2022 *)

%o (PARI) Vec(x*(-2-151*x+3*x^2)/((x-1)*(x^2-302*x+1)) + O(x^30)) \\ _Colin Barker_, Oct 18 2014

%Y Cf. A145123.

%K easy,nonn

%O 1,1

%A _Richard Choulet_, Oct 02 2008

%E Editing and more terms from _Colin Barker_, Oct 18 2014

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Last modified September 21 03:31 EDT 2024. Contains 376079 sequences. (Running on oeis4.)