%I
%S 2,7,8,9,11,12,15,20,21,27,29,30,32,34,38,44,50,52,53,54,55,56,58,59,
%T 60,62,64,65,68,70,73,74,77,78,80,83,85,86,89,91,95,98,101,108,109,
%U 110,114,116,120,127,128,134,136,137,138,139,140,141,143,144,145,146,147,150,151,152,154,155,157,158,159,162
%N a(n) = position of nth 0 when sequence is written in base 2.
%C A167500 lists the positions of 1s when the sequence is written in binary. This sequence lists the positions of 0s. When written in binary, it begins 10, 111, 1000, 1001, 1011... The first 0 appears at position 2, so a(1) = 2 = 10. The second 0 appears at position 7, so a(2) = 7 = 111. The third 0 appears at position 8, so a(3) = 8 = 1000. The sequence then becomes selfgenerating, because entries are added to it faster than 0s are detected in it.
%H Anthony Sand, <a href="/A287515/b287515.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = zeropos([sequence],n)
%e a(1) = zeropos([10...],1) = 2
%e a(2) = zeropos([10,111,1000...],2) = 7
%e a(3) = zeropos([10,111,1000...],3) = 8
%e a(4) = zeropos([10,111,1000...],4) = 9
%e a(5) = zeropos([10,111,1000,1001...],5) = 11
%o (PARI) { zeroposseq()= smx=100; s=vector(smx); s[1]=2; s[2]=7; s[3]=8; si=0; dig=digits(s[1],2); di=1; i=1; dl=0; while(si<smx, d=dig[i]; dl++; if(d==0, si++; s[si]=dl; print1(dl,", "); ); i++; if(i>#dig, di++; dig=digits(s[di],2); i=1; ); ); }
%Y Cf. A167500, A167502.
%K nonn,base,easy
%O 1,1
%A _Anthony Sand_, May 26 2017
