OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..250
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
From Reinhard Zumkeller, Jan 29 2009: (Start)
a(n) = 27*A000578(n).
a(n) = A155955(n,3) for n>2. - Reinhard Zumkeller, Jan 31 2009
G.f.: 27*x*(1+4*x+x^2)/(x-1)^4 . - R. J. Mathar, Jul 07 2017
E.g.f.: 27*x*(1 + 3*x + x^2)*exp(x). - G. C. Greubel, Sep 15 2018
a(n) = -a(-n) for all n in Z. - Michael Somos, Sep 16 2018
EXAMPLE
G.f. = 27*x + 216*x^2 + 729*x^3 * 1728*x^4 + 3375*x^5 + 5832*x^6 + ... - Michael Somos, Sep 16 2018
MATHEMATICA
Table[(3*n)^3, {n, 0, 30}] (* G. C. Greubel, Sep 15 2018 *)
PROG
(Magma) [(3*n)^3: n in [0..40]]; // Vincenzo Librandi, Jul 29 2011
(PARI) a(n)=27*n^3 \\ Charles R Greathouse IV, Jul 29 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved