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A170877 Number of binary words of length n with properties that there is no pair of adjacent 1's and no subword of the form X^4 for any string X. 1

%I #9 Aug 22 2013 03:35:58

%S 1,2,3,5,7,10,15,22,30,43,61,88,123,173,246,348,487,688,972,1371,1928,

%T 2714,3822,5387,7582,10681,15046,21194,29835,42009,59159,83305,117292,

%U 165170,232593,327530,461198,649431,914493,1287747,1813281,2553346,3595465

%N Number of binary words of length n with properties that there is no pair of adjacent 1's and no subword of the form X^4 for any string X.

%C The subword 01010101 (corresponding to X = 01) for example cannot occur.

%H Lars Blomberg, <a href="/A170877/b170877.txt">Table of n, a(n) for n = 0..43</a>

%e a(3) = 5: 000, 001, 010, 100, 101.

%e a(4) = 7: 0001, 0010, 0100, 1000, 0101, 1010, 1001.

%Y Cf. A003410, A028445, A135491.

%K nonn

%O 0,2

%A _Benjamin Chaffin_ and _N. J. A. Sloane_, Jan 07 2010

%E a(24)-a(42) from _Lars Blomberg_, Aug 22 2013

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Last modified June 23 10:35 EDT 2024. Contains 373643 sequences. (Running on oeis4.)