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A102345 a(n) = 3^n + (-1)^n. 6
2, 2, 10, 26, 82, 242, 730, 2186, 6562, 19682, 59050, 177146, 531442, 1594322, 4782970, 14348906, 43046722, 129140162, 387420490, 1162261466, 3486784402, 10460353202, 31381059610, 94143178826, 282429536482, 847288609442 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
a(n) = A105723(n) + 2*(-1)^n; (a(n) + A105723(n))/2 = A000244(n). - Reinhard Zumkeller, Apr 18 2005
LINKS
FORMULA
a(n) = 2*a(n-1) + 3*a(n-2).
From Elmo R. Oliveira, Dec 18 2023: (Start)
G.f.: 2*(1-x)/((1+x)*(1-3*x)).
E.g.f.: exp(-x) + exp(3*x).
a(n) = 2*A046717(n). (End)
MATHEMATICA
Table[3^n+(-1)^n, {n, 0, 30}] (* or *) LinearRecurrence[{2, 3}, {2, 2}, 30] (* Harvey P. Dale, Jun 19 2016 *)
PROG
(Sage) [lucas_number2(n, 2, -3) for n in range(0, 26)] # Zerinvary Lajos, Apr 30 2009
CROSSREFS
Apart from leading term, same as A084182.
Sequence in context: A341680 A213338 A309753 * A151364 A200949 A001885
KEYWORD
easy,nonn
AUTHOR
Graeme McRae, Feb 16 2005
STATUS
approved

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Last modified March 19 07:25 EDT 2024. Contains 370955 sequences. (Running on oeis4.)