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A153259
a(n) = n^3 - (3*(n+3))^2.
2
-81, -143, -217, -297, -377, -451, -513, -557, -577, -567, -521, -433, -297, -107, 143, 459, 847, 1313, 1863, 2503, 3239, 4077, 5023, 6083, 7263, 8569, 10007, 11583, 13303, 15173, 17199, 19387, 21743, 24273, 26983, 29879, 32967, 36253, 39743, 43443, 47359
OFFSET
1,1
FORMULA
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4), a(1)=-81, a(2)=-143, a(3)=-217, a(4)=-297. - Harvey P. Dale, Jul 10 2013
From Elmo R. Oliveira, Sep 08 2025: (Start)
G.f.: x*(-81 + 181*x - 131*x^2 + 37*x^3)/(x-1)^4.
E.g.f.: exp(x)*(-81 - 62*x - 6*x^2 + x^3). (End)
MATHEMATICA
a[n_]:=n^3-(3*(n+3))^2; lst={}; Do[AppendTo[lst, a[n]], {n, 0, 5!}]; lst
Table[n^3-(3(n+3))^2, {n, 0, 40}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {-81, -143, -217, -297}, 40] (* Harvey P. Dale, Jul 10 2013 *)
PROG
(PARI) a(n)=n^3-(3*n+9)^2 \\ Charles R Greathouse IV, Oct 18 2022
CROSSREFS
KEYWORD
sign,easy
AUTHOR
STATUS
approved