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A133448 a(n)=3a(n-1)-a(n-3)+3a(n-4). 1
2, 5, 13, 40, 121, 365, 1094, 3281 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

Sum of digits mod 9: 2, 5, 4, 4, 4, 5, 5, 5, ..., is hexaperiodic.

FORMULA

a(n)=(1/3)*{1/2-(1/2)*I]*sqrt(3)}^n+(3/2)*3^n-(1/6)*(-1)^n+(1/3)*{1/2+(1/2)*I*sqrt(3)}^n, with n>=0 and I=sqrt(-1) - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 09 2008

CROSSREFS

Sequence in context: A148305 A104447 A127986 * A149862 A149863 A202153

Adjacent sequences:  A133445 A133446 A133447 * A133449 A133450 A133451

KEYWORD

nonn

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Nov 27 2007

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Last modified February 16 23:45 EST 2012. Contains 205978 sequences.