OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
From Harvey P. Dale, Jun 18 2011: (Start)
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4), a(0)=0, a(1)=125, a(2)=1000, a(3)=3375.
G.f.: 125*x*(1+4*x+x^2)/(x-1)^4. (End)
a(n) = 125*A000578(n). - Michel Marcus, Feb 14 2014
From Elmo R. Oliveira, Oct 16 2025: (Start)
E.g.f.: 125*exp(x)*x*(1 + 3*x + x^2).
a(n) = A000578(5*n). (End)
MATHEMATICA
(5Range[0, 30])^3 (* or *) LinearRecurrence[{4, -6, 4, -1}, {0, 125, 1000, 3375}, 30] (* Harvey P. Dale, Jun 18 2011 *)
PROG
(PARI) a(n) = 125*n^3; \\ Michel Marcus, Feb 14 2014
(Magma) [(5*n)^3: n in [0..40]]; // Vincenzo Librandi, Feb 14 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Michel Marcus, Feb 14 2014
STATUS
approved
