cp's OEIS Frontend

A379471 Composition of bijective bit-reverse and Blue code, in this order: a(n) = A193231(A057889(n)).

%I A379471 #9 Dec 25 2024 10:54:43
%S A379471 0,1,3,2,5,4,6,7,15,14,12,11,10,13,9,8,17,16,18,31,20,21,29,26,30,19,
%T A379471 23,28,27,22,24,25,51,50,48,35,54,61,33,44,60,55,63,38,39,56,46,41,34,
%U A379471 49,53,32,57,62,36,47,45,52,58,37,40,59,43,42,85,84,86,103,80,69,101,118,90,91,71,104,99,74,116,121
%N A379471 Composition of bijective bit-reverse and Blue code, in this order: a(n) = A193231(A057889(n)).
%H A379471 Antti Karttunen, <a href="/A379471/b379471.txt">Table of n, a(n) for n = 0..16383</a>
%H A379471 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%H A379471 <a href="/index/Ge#GF2X">Index entries for sequences related to polynomials in ring GF(2)[X]</a>
%H A379471 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%o A379471 (PARI)
%o A379471 A030101(n) = if(n<1,0,subst(Polrev(binary(n)),x,2));
%o A379471 A057889(n) = if(!n,n,A030101(n/(2^valuation(n,2))) * (2^valuation(n, 2)));
%o A379471 A193231(n) = { my(x='x); subst(lift(Mod(1, 2)*subst(Pol(binary(n), x), x, 1+x)), x, 2) };
%o A379471 A379471(n) = A193231(A057889(n));
%Y A379471 Cf. A057889, A193231, A379472 (inverse permutation).
%K A379471 nonn,base,easy
%O A379471 0,3
%A A379471 _Antti Karttunen_, Dec 25 2024