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 A359858 #10 Jan 16 2023 09:07:41 %S A359858 0,2,6,5,3,8,14,18,20,12,24,23,9,27,37,10,22,25,7,40,39,52,42,49,15, %T A359858 32,59,35,56,38,53,41,50,44,47,81,13,78,16,75,57,34,94,61,30,98,60,31, %U A359858 97,58,33,122,63,28,127,55,36,126,65,118,67,95,88,74,109,76,86,99,84,101,82,80,103,187 %N A359858 a(0) = 0; for n > 0, a(n) is the smallest positive number not occurring earlier such that the ones' complement of the binary string of a(n-1) + a(n) does not appear in the binary string concatenation of a(0)..a(n-1). %C A359858 In the first 100000 terms the fixed points are 55, 123, 1779, 2009, although it is likely more exist. The sequence is conjectured to be a permutation of the positive integers. Note that 1 does not appear until the 160th term. %H A359858 Scott R. Shannon, <a href="/A359858/a359858.png">Image of the first 50000 terms</a>. The green line is a(n) = n. Note some of the patterns appearing are reminiscent of those in the images of A357082. %e A359858 a(3) = 5 as the concatenation of a(0)..a(2) in binary is "010110" and a(2) + 5 = 6 + 5 = 11 = 1011_2 whose ones' complement = 100_2, which does not appear in the concatenated string. Note the ones' complements of 6+1, 6+3, 6+4 are 0_2, 110_2, 101_2, all of which appear in the concatenated string. %Y A359858 Cf. A035327, A007088, A357082, A355611. %K A359858 nonn,base,look %O A359858 0,2 %A A359858 _Scott R. Shannon_, Jan 16 2023