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 A045695 Number of ternary words of length n (beginning 0) with autocorrelation function 2^(n-1)+1. 1

%I

%S 0,1,2,8,22,70,202,622,1844,5576,16658,50114,150140,450824,1351850,

%T 4056794,12168538,36509302,109522330,328578142,985717768,2957186620,

%U 8871509746,26614629466,79843738258,239531515054,718594094338

%N Number of ternary words of length n (beginning 0) with autocorrelation function 2^(n-1)+1.

%F a(2n) = 3*a(2n-1) + 2*a(n) for n >= 2; a(2n-1) = 3*a(2n-2) - a(n) for n >= 2

%p A045695 := proc(n)

%p if n <=2 then

%p n-1 ;

%p elif type(n,'even') then

%p 3*procname(n-1)+2*procname(n/2) ;

%p else

%p 3*procname(n-1)-procname((n+1)/2) ;

%p end if;

%p end proc: # _R. J. Mathar_, Oct 04 2014

%K nonn

%O 1,3

%A TORSTEN.SILLKE(AT)LHSYSTEMS.COM

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Last modified January 26 07:27 EST 2022. Contains 350575 sequences. (Running on oeis4.)