A357166 - OEIS

%I #12 Sep 16 2022 07:42:21

%S 0,1,2,3,4,5,7,9,23,8,6,16,11,13,49,18,14,10,15,19,12,17,47,20,24,41,

%T 22,26,34,38,28,29,31,30,27,37,33,25,21,40,32,36,46,39,35,82,51,42,78,

%U 45,48,44,74,43,52,65,67,69,50,62,60,58,53,55,87,54,56,57

%N If n appears in A357082, then a(n) is the unique k such that A357082(k) = n; otherwise a(n) = -1.

%H Rémy Sigrist, <a href="/A357166/b357166.txt">Table of n, a(n) for n = 0..10000</a>

%H Rémy Sigrist, <a href="/A357166/a357166.gp.txt">PARI program</a>

%H Rémy Sigrist, <a href="/A357166/a357166.pl.txt">Perl program</a>

%e A357082(42) = 47, hence a(47) = 42.

%o (PARI) See Links section.

%o (Perl) See Links section.

%o (Python)

%o from itertools import islice

%o def agen():

%o     aset, appearsat, astr, an, mink, nn = {0}, {0: 0}, "0", 0, 1, 0

%o     for n in count(1):

%o         k = mink

%o         while k in aset or bin(an+k)[2:] in astr: k += 1

%o         while mink in aset: mink += 1

%o         an = k; aset.add(an); astr += bin(an)[2:]; appearsat[an] = n

%o         while nn in appearsat: yield appearsat[nn]; nn += 1

%o print(list(islice(agen(), 68))) # _Michael S. Branicky_, Sep 16 2022

%Y Cf. A357082.

%K nonn,look,base

%O 0,3

%A _Rémy Sigrist_, Sep 16 2022