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A114803
Integers when g2^3-27*g3^2=0 in cubic polynomials of the form: w^2=4*x^3-g2*x-g3.
0
1, 3, 8, 12, 27, 27, 64, 48, 125, 75, 216, 108, 343, 147, 512, 192, 729, 243, 1000, 300, 1331, 363, 1728, 432, 2197, 507, 2744, 588, 3375, 675, 4096, 768, 4913, 867
OFFSET
0,2
COMMENTS
When the elliptic term: j=g2^3/(g2^3-27*g3^2) is singular and g2 and g3 are both integers.
FORMULA
a(n) = If 3*n^(2/3) is an integer then {n,3*n^(2/3)}
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
MATHEMATICA
a = Flatten[Table[If[IntegerQ[3*n^(2/3)] == True, {n, 3*n^(2/3)}, {}], {n, 1, 5000}]]
CROSSREFS
Sequence in context: A326890 A024463 A092954 * A083171 A058582 A178720
KEYWORD
nonn,uned,easy
AUTHOR
Roger L. Bagula, Feb 18 2006
STATUS
approved