# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a303786 Showing 1-1 of 1 %I A303786 #9 Apr 30 2018 11:32:26 %S A303786 1,11,1011,10001011,1000000010001011,10000000000000001000000010001011, %T A303786 1000000000000000000000000000000010000000000000001000000010001011, %U A303786 10000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000010000000000000001000000010001011 %N A303786 Lexicographically earliest sequence of distinct terms such that what emerges from the mask rebuilds the sequence itself, term by term (see the Comment section for the mask explanation). %C A303786 For any pair of contiguous terms, one of the terms uses fewer digits than the other. This term is called the mask. Put the mask on the other term, starting from the left. What is not covered by the mask rebuilds, term by term, the starting sequence. %C A303786 The n-th term of the sequence has exactly 2^(n-1) digits, which means that a(21) has more than one million digits. %C A303786 The sequence starts with a(1) = 1, then a(n) = 10^(2^(n-1)-1)+a(n-1). %H A303786 Jean-Marc Falcoz, Table of n, a(n) for n = 1..11 %e A303786 In the pair (1,11), 1 is the mask; 1 emerges = a(1); %e A303786 In the pair (11,1011), 11 is the mask; 11 emerges = a(2); %e A303786 In the pair (1011,10001011), 1011 is the mask; 1011 emerges = a(3); etc. %Y A303786 Cf. A303782 (same idea with primes), A303783 (with squares), A303784 (with even numbers), A303785 (with odd numbers). %K A303786 nonn,base %O A303786 1,2 %A A303786 _Eric Angelini_ and _Jean-Marc Falcoz_, Apr 30 2018 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE