%I #7 Aug 21 2021 15:42:44
%S 1,2,10,20,3,4,7,8,30,40,107,5,80,9,6,15,11,206,19,12,13,21,111,50,
%T 300,120,131,90,140,14,210,16,17,18,25,26,31,41,29,23,160,170,180,22,
%U 27,502,51,260,802,33,1290,24,32,200,410,270,34,1070,35,28,37,42,47,330
%N There are a(n) digits between a(n) and the next copy of the string a(n). This is the lexicographically earliest sequence of distinct positive terms with this property.
%C A selfdescribing sequence.
%e a(1) = 1; there is 1 digit between a(1) and the "1" of 10: this is the digit 2;
%e a(2) = 2; there are 2 digits between a(2) and the "2" of 20: they are 1 and 0;
%e a(3) = 10; there are 10 digits between a(3) and the "10" of 107: they are 2, 0, 3, 4, 7, 8, 3, 0, 4 and 0;
%e a(4) = 20; there are 20 digits between a(4) and the "20" of 206: they are 3, 4, 7, 8, 3, 0, 4, 0, 1, 0, 7, 5, 8, 0, 9, 6, 1, 5, 1 and 1;
%e a(5) = 3; there are 3 digits between a(5) and the "3" of 30: they are 4, 7 and 8;
%e a(6) = 4; there are 4 digits between a(6) and the "4" of 40: they are 7, 8, 3 and 0;
%e a(7) = 7; there are 7 digits between a(7) and the "7" of 107: they are 8, 3, 0, 4, 0, 1 and 0; etc.
%Y Cf. A303151.
%K base,nonn
%O 1,2
%A _Eric Angelini_ and _Carole Dubois_, Aug 05 2021
