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a(n) is the largest k such that A255070(k) = n.
9

%I #17 Mar 23 2021 16:20:05

%S 2,5,6,10,11,13,14,18,21,22,23,26,27,29,30,34,37,38,42,43,45,46,47,50,

%T 53,54,55,58,59,61,62,66,69,70,74,75,77,78,82,85,86,87,90,91,93,94,95,

%U 98,101,102,106,107,109,110,111,114,117,118,119,122,123,125,126,130,133,134,138,139,141,142,146,149,150

%N a(n) is the largest k such that A255070(k) = n.

%H Antti Karttunen, <a href="/A255068/b255068.txt">Table of n, a(n) for n = 0..8192</a>

%H Kevin Ryde, <a href="http://user42.tuxfamily.org/dragon/index.html">Iterations of the Dragon Curve</a>, see index TurnRight, with a(n) = TurnRight(n) - 1.

%F a(n) = A091067(n+1) - 1.

%o (Scheme) (define (A255068 n) (- (A091067 (+ n 1)) 1))

%o (PARI) a(n) = my(t=1); n=2*n+2; forstep(i=logint(n,2),0,-1, if(bittest(n,i)==t, n++;t=!t)); n-1; \\ _Kevin Ryde_, Mar 21 2021

%Y First differences are A106836 (from its second term onward).

%Y Cf. A091067, A255070, A255327.

%Y Sequence A341522 sorted into ascending order.

%K nonn

%O 0,1

%A _Antti Karttunen_, Feb 21 2015