cp's OEIS Frontend

A332795 Lexicographically earliest sequence of distinct positive terms such that a(n) and a(n+1) are substrings of their product.

%I A332795 #19 Aug 14 2025 04:25:20
%S A332795 1,10,11,100,21,1000,31,10000,41,100000,51,1000000,61,10000000,71,
%T A332795 100000000,81,2817
%N A332795 Lexicographically earliest sequence of distinct positive terms such that a(n) and a(n+1) are substrings of their product.
%C A332795 From _Giovanni Resta_, Feb 26 2020: (Start)
%C A332795 a(19) = 87281795511221945137157107231920199501246882793017456359
%C A332795   1022443890274314214463840399002493765586034912718204488778054862
%C A332795   8428927680798004987531172069825436408977556109725685785536159601,
%C A332795 which is too large (184 digits) to be included in Data.
%C A332795 Here a(18)*a(19) = 245|a(19)|7 = 24587|a(18)|955... where | denotes digit concatenation. (End)
%e A332795 a(1)*a(2) = 1*10 = 10 and 10 contains the substrings 1 and 10, which are precisely a(1) and a(2);
%e A332795 a(17)*a(18) = 81*2817 = 228177 and 228177 contains the substrings 81 and 2817, which are precisely a(17) and a(18).
%Y A332795 Cf. A066217.
%K A332795 nonn,base
%O A332795 1,2
%A A332795 _Eric Angelini_ and _Carole Dubois_, Feb 24 2020