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 A214809 #27 Jan 16 2024 12:11:48 %S A214809 2,1,0,4,0,3,0,0,1,1,3,1,6,4,0,0,0,4,2,0,1,2,4,2,1,1,0,0,7,0,0,3,0,1, %T A214809 0,8,1,5,0,0,3,1,0,1,0,0,1,1,4,0,0,1,1,0,0,0,0,3,1,1,2,0,2,2,0,1,5,1, %U A214809 3,2,0,0,4,0,0,1,2,5,8,6,4,11,3,8,0,0,1,0,6,4,2,1,0,0,2,9,5,1,0,0,2,0,0,3,3,1,5,3,2,7,5,0,4,0,5,0,1,1,2,0 %N A214809 A214330 prefixed by a 0 consists of a concatenation of strings 0111010(01)^n, each such string ending with n >= 0 copies of 10; sequence gives successive values of n. %C A214809 If we change the three initial terms of A214551 (as in A214331 and A214626), again read the sequence mod 2, and decompose the result into strings 0111010(01)^n, will the sequence of values of n have anything in common with the current sequence? Is A214809 in any way characteristic of this family of sequences? %H A214809 N. J. A. Sloane, <a href="/A214809/b214809.txt">Table of n, a(n) for n = 1..916</a> %H A214809 N. J. A. Sloane, <a href="/A214330/a214330.jpg">State diagram</a> [State diagram for A214551 mod 2 for any three initial terms. Nodes are labeled with a(n-2) a(n-1) a(n), edges are labeled with a(n+1).] %e A214809 Let s = 0111010. Then 0, A214330 starts %e A214809 s1010s10ss10101010ss101010sss10s10s101010s10s101010101010s10101010ssss101\ %e A214809 01010s1010ss10s1010s10101010s1010s10s10sss10101010101010sss101010ss10ss10\ %e A214809 10101010101010s10s1010101010sss101010s10ss10sss10s10s10101010sss10s10ssss\ %e A214809 s101010s10s10s1010ss1010s1010ss10s1010101010s10s101010s1010sss10101010sss\ %e A214809 ..., in which the successive numbers of 10's are 2, 1, 0, 4, 0, 3, 0, 0, ... %o A214809 (Shell) # Using b-file for A214330, condense 10000 terms into one long string; prefix with 0. %o A214809 # Using vi, s/0111010/s/g; then s/10/a/g; %o A214809 # Using tr, break up so that there is one s per line. %o A214809 # Using awk, count the a's per line. %Y A214809 Cf. A214330, A214551. %K A214809 nonn %O A214809 1,1 %A A214809 _N. J. A. Sloane_, Jul 30 2012