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(3^k - 1)/2 appears 3^(k-1) times, k>0.
3

%I #4 May 30 2021 14:15:44

%S 1,4,4,4,13,13,13,13,13,13,13,13,13,40,40,40,40,40,40,40,40,40,40,40,

%T 40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,40,121,121,121,121,121,

%U 121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121,121

%N (3^k - 1)/2 appears 3^(k-1) times, k>0.

%F a(n+1) = 3*a(floor(n/3)) + 1; a(0) = 1.

%t Table[PadRight[{},3^(k-1),(3^k-1)/2],{k,5}]//Flatten (* _Harvey P. Dale_, May 30 2021 *)

%Y Cf. A003462, A007448, A003817.

%K nonn

%O 0,2

%A _Reinhard Zumkeller_, Jul 18 2010

%E Erroneous comment deleted by _Reinhard Zumkeller_, Jul 23 2010