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%I #11 May 20 2022 05:24:46

%S 0,0,1,0,2,2,3,0,4,4,5,4,6,6,7,0,8,8,9,8,10,10,11,8,12,12,13,12,14,14,

%T 15,0,16,16,17,16,18,18,19,16,20,20,21,20,22,22,23,16,24,24,25,24,26,

%U 26,27,24,28,28,29,28,30,30,31,0,32,32,33,32,34,34,35,32,36,36,37,36,38,38,39

%N A129760/2.

%C a(n) is the degree of the n-th Stern polynomial defined in Beck and Dilcher. - _Michel Marcus_, May 20 2022

%H George Beck and Karl Dilcher, <a href="https://arxiv.org/abs/2106.10400">A Matrix Related to Stern Polynomials and the Prouhet-Thue-Morse Sequence</a>, arXiv:2106.10400 [math.CO], 2021.

%H R. Brown and J. L. Merzel, <a href="http://www.fq.math.ca/Papers1/45-2/brown.pdf">The number of Ducci sequences with a given period</a>, Fib. Quart., 45 (2007), 115-121.

%p a:= n-> Bits[And](n, n-1)/2:

%p seq(a(n), n=1..100); # _Alois P. Heinz_, May 20 2022

%o (PARI) a(n) = bitand(n, n-1)/2; \\ _Michel Marcus_, Sep 06 2017

%Y Cf. A129760.

%K nonn

%O 1,5

%A _N. J. A. Sloane_, May 25 2008