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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

Table of n, a(n) for n=0..25.

Index entries for linear recurrences with constant coefficients, signature (2,3).

FORMULA

a(n) = 3a(n-2) + 2a(n-1).

MAPLE

g:=1/(1+3*z): gser:=series(g, z=0, 43): seq(abs(coeff(gser, z, n)+1), n=0..31); # Zerinvary Lajos, Jan 09 2009

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 xrange(0, 26)] # Zerinvary Lajos, Apr 30 2009

CROSSREFS

Apart from leading term, same as A084182.

Sequence in context: A151428 A213338 A309753 * A151364 A200949 A001885

Adjacent sequences:  A102342 A102343 A102344 * A102346 A102347 A102348

KEYWORD

easy,nonn

AUTHOR

Graeme McRae, Feb 16 2005

STATUS

approved

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Last modified November 14 09:51 EST 2019. Contains 329111 sequences. (Running on oeis4.)