This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A106485 #13 Jul 23 2025 17:08:01 %S A106485 0,2,1,3,32,34,33,35,16,18,17,19,48,50,49,51,8,10,9,11,40,42,41,43,24, %T A106485 26,25,27,56,58,57,59,4,6,5,7,36,38,37,39,20,22,21,23,52,54,53,55,12, %U A106485 14,13,15,44,46,45,47,28,30,29,31,60,62,61,63,128,130,129,131,160,162 %N A106485 CGT-tree negating involution of nonnegative integers. %C A106485 This involution negates game trees used in the combinatorial game theory, when they are encoded in the way explained in A106486. %C A106485 Cycles are confined into ranges [a(n),a(n+1)[, where a(0)=0 and a(n+1)=2^(2*a(n)), i.e. the ranges are [0,0], [1,3], [4,255], [256,(2^512)-1], ... %H A106485 Antti Karttunen, <a href="/A106485/b106485.txt">Table of n, a(n) for n = 0..1023</a> %H A106485 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A106485 (Scheme) (define (A106485 n) (let loop ((n n) (i 0) (s 0)) (cond ((zero? n) s) ((odd? n) (loop (/ (- n 1) 2) (1+ i) (+ s (if (even? i) (expt 2 (+ 1 (* 2 (A106485 (/ i 2))))) (expt 2 (* 2 (A106485 (/ (- i 1) 2)))))))) (else (loop (/ n 2) (1+ i) s))))) %Y A106485 A057300 is a "shallow" version which just swaps the left and right options of the game tree, but does not reflect the subtrees themselves. Cf. A106486-A106487. %K A106485 nonn %O A106485 0,2 %A A106485 _Antti Karttunen_, May 21 2005