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

1, 10, 11, 100, 21, 1000, 31, 10000, 41, 100000, 51, 1000000, 61, 10000000, 71, 100000000, 81, 2817

Offset: 1

Author

Eric Angelini and Carole Dubois, Feb 24 2020

Keywords

• nonn
• base

Comments

From Giovanni Resta, Feb 26 2020: (Start)

a(19) = 87281795511221945137157107231920199501246882793017456359

1022443890274314214463840399002493765586034912718204488778054862

8428927680798004987531172069825436408977556109725685785536159601,

which is too large (184 digits) to be included in Data.

Here a(18)*a(19) = 245|a(19)|7 = 24587|a(18)|955... where | denotes digit concatenation. (End)

Examples

			a(1)*a(2) = 1*10 = 10 and 10 contains the substrings 1 and 10, which are precisely a(1) and a(2);
a(17)*a(18) = 81*2817 = 228177 and 228177 contains the substrings 81 and 2817, which are precisely a(17) and a(18).
		

Crossrefs

Cf. A066217.