A128785 a(n) = n^2*6^n.
0, 6, 144, 1944, 20736, 194400, 1679616, 13716864, 107495424, 816293376, 6046617600, 43898443776, 313456656384, 2207257288704, 15359376162816, 105791621529600, 722204136308736, 4891804579528704, 32905425960566784
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (18,-108,216).
Programs
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Magma
[n^2*6^n: n in [0..20]]; // Vincenzo Librandi, Oct 04 2011
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Mathematica
Table[n^2 6^n,{n,0,30}] (* or *) LinearRecurrence[{18,-108,216},{0,6,144},30] (* Harvey P. Dale, Oct 03 2011 *)
Formula
From R. J. Mathar, Jul 25 2009: (Start)
a(n) = 18*a(n-1) - 108*a(n-2) + 216*a(n-3).
G.f.: -6*x*(1+6*x)/(6*x-1)^3. (End)