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A145123 Numbers n such that there exists x in N : (x+1)^3-x^3=19*n^2. 4
1, 301, 90901, 27451801, 8290353001, 2503659154501, 756096774306301, 228338722181348401, 68957538001992910801, 20824948137879677713501, 6289065380101660676566501, 1899276919842563644645369801 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n+2) = 302*a(n+1)-a(n).
G.f.: -x*(-1+x) / ( 1-302*x+x^2 ). - R. J. Mathar, Nov 27 2011
EXAMPLE
a(1)=1 because 3^3-2^3=19*1.
MATHEMATICA
CoefficientList[Series[(1 - x)/(1 - 302 x + x^2), {x, 0, 20}], x] (* Vincenzo Librandi, Oct 18 2014 *)
PROG
(PARI) Vec(-x*(-1+x)/(1-302*x+x^2) + O(x^30)) \\ Colin Barker, Oct 18 2014
CROSSREFS
Cf. A145124.
Sequence in context: A178267 A296961 A028499 * A068258 A075407 A258449
KEYWORD
easy,nonn
AUTHOR
Richard Choulet, Oct 02 2008
EXTENSIONS
Editing and more terms from Colin Barker, Oct 18 2014
STATUS
approved

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Last modified June 12 19:52 EDT 2024. Contains 373360 sequences. (Running on oeis4.)