|
|
A145334
|
|
Numbers x such that (x+43)^3-x^3 is a square.
|
|
1
|
|
|
1118, 38413663, 1294925303334, 43651931937700199, 1471506624324949129678, 49604488262342103224469903, 1672167297852045675371932025174, 56368759560987971454445725344870359, 1900190883128737219877319726003648501438
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
a(n+2) = 33710*a(n+1)-a(n)+724722.
G.f.: 43*x*(27*x^2-16855*x-26) / ((x-1)*(x^2-33710*x+1)). - Colin Barker, Oct 21 2014
|
|
EXAMPLE
|
a(1)=1118 because the first relation is : (1118+43)^3-1118^3=12943^2.
|
|
MATHEMATICA
|
CoefficientList[Series[43 (27 x^2 - 16855 x - 26)/((x - 1) (x^2 - 33710 x + 1)), {x, 0, 20}], x] (* Vincenzo Librandi, Oct 21 2014 *)
LinearRecurrence[{33711, -33711, 1}, {1118, 38413663, 1294925303334}, 20] (* Harvey P. Dale, Feb 22 2017 *)
|
|
PROG
|
(PARI) Vec(43*x*(27*x^2-16855*x-26)/((x-1)*(x^2-33710*x+1)) + O(x^20)) \\ Colin Barker, Oct 21 2014
(Magma) I:=[1118, 38413663, 1294925303334]; [n le 3 select I[n] else 33711*Self(n-1)-33711*Self(n-2)+Self(n-3): n in [1..10]]; // Vincenzo Librandi, Oct 21 2014
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|