cp's OEIS Frontend

A359611 The lexicographically earliest "Increasing Term Fractal Jump Sequence".

%I A359611 #15 Jan 30 2023 07:42:52
%S A359611 1,2,20,22,100,200,201,1000,20000,20001,110000,2000000,2000001,
%T A359611 110100000,200000000,200000001,1101001000000,2000000000020,
%U A359611 2000000010101,10100010000000,20000000000002,20020000000001,101001010010000,100000000200000000000000
%N A359611 The lexicographically earliest "Increasing Term Fractal Jump Sequence".
%C A359611 The rules of an "Increasing Term Fractal Jump Sequence" are described in A105647.
%C A359611 We define a "forced" digit in Fractal Jump Sequences as a digit that is required to be a specific value by a digit that occurred previously in the sequence. This is in opposition to digits that could have any value selected for them without breaking the Fractal Jump Sequence rules. In the diagram below, the digits with carets below them are the forced digits.
%C A359611 To find a(n), increment a(n-1) until all of the forced digits that will positionally occur in a(n) satisfy their forced values. Then, to avoid leading zeros in a(n+1), if there are forced zeros immediately following the candidate a(n), continue to increment until it is the same number of digits longer as there are consecutive forced zeros, and continue to increment until the candidate a(n) once again satisfies all forcing criteria (including the new zeros).
%C A359611 The only digits that appear in this sequence are 0, 1, and 2, even though no numerals are arbitrarily restricted from appearing.
%e A359611 The sequence and the "kept"/"forced" digits begin
%e A359611   1, 2, 20, 22, 100, 200, 201, 1000, 20000, ...
%e A359611   ^     ^    ^    ^  ^    ^    ^ ^^  ^  ^^
%e A359611   1     2    2    0  2    2    1 00  2  00
%e A359611 In the case of computing a(5), we have a 22 for a(4), so we would normally increment to 23, as there is nothing forcing the next two digits. However, since there is a 0 forcing the following digit, we must increment to the smallest number that satisfies this forced 0 (as we can't have leading zeros in a(6)).
%Y A359611 Cf. A359385 (no zeros), A105647, A105395, A105396, A105397, A105398.
%K A359611 nonn,base
%O A359611 1,2
%A A359611 _Tyler Busby_, Jan 06 2023