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A128797 (n^2-n)*3^n. 1
0, 0, 18, 162, 972, 4860, 21870, 91854, 367416, 1417176, 5314410, 19486170, 70150212, 248714388, 870500358, 3013270470, 10331213040, 35126124336, 118550669634, 397493421714, 1324978072380, 4393348345260, 14498049539358 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
G.f.: 18*x^2/(1-3*x)^3. - Vincenzo Librandi, Feb 10 2013
a(n) = 18*A027472(n+1). - R. J. Mathar, Apr 26 2015
MATHEMATICA
CoefficientList[Series[18 x^2/(1 - 3 x)^3, {x, 0, 30}], x] (* Vincenzo Librandi, Feb 10 2013 *)
LinearRecurrence[{9, -27, 27}, {0, 0, 18}, 40] (* Harvey P. Dale, Dec 15 2014 *)
PROG
(Magma) [(n^2-n)*3^n: n in [0..25]]; // Vincenzo Librandi, Feb 10 2013
CROSSREFS
Sequence in context: A171642 A158808 A271899 * A008418 A099196 A041618
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Apr 07 2007
STATUS
approved

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Last modified May 30 03:00 EDT 2024. Contains 372957 sequences. (Running on oeis4.)