The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A114803 Integers when g2^3-27*g3^2=0 in cubic polynomials of the form: w^2=4*x^3-g2*x-g3. 0

%I #8 Jun 13 2015 00:52:02

%S 1,3,8,12,27,27,64,48,125,75,216,108,343,147,512,192,729,243,1000,300,

%T 1331,363,1728,432,2197,507,2744,588,3375,675,4096,768,4913,867

%N Integers when g2^3-27*g3^2=0 in cubic polynomials of the form: w^2=4*x^3-g2*x-g3.

%C When the elliptic term: j=g2^3/(g2^3-27*g3^2) is singular and g2 and g3 are both integers.

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,4,0,-6,0,4,0,-1).

%F a(n) = If 3*n^(2/3) is an integer then {n,3*n^(2/3)}

%F a(n) = (n^3+6*n^2+12*n+8)/8 for n even. a(n) = (3*n^2+6*n+3)/4 for n odd. G.f.: -(3*x^5-x^4-4*x^2-3*x-1) / ((x-1)^4*(x+1)^4). - _Colin Barker_, Mar 15 2013

%t a = Flatten[Table[If[IntegerQ[3*n^(2/3)] == True, {n, 3*n^(2/3)}, {}], {n, 1, 5000}]]

%K nonn,uned,easy

%O 0,2

%A _Roger L. Bagula_, Feb 18 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 6 15:20 EDT 2023. Contains 363148 sequences. (Running on oeis4.)