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

1,2

Comments

From Giovanni Resta, Feb 26 2020: (Begin)

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)

Links

Table of n, a(n) for n=1..18.

Example

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.

Sequence in context: A153069 A332703 A178569 * A303605 A266946 A081551

Adjacent sequences: A332792 A332793 A332794 * A332796 A332797 A332798

Keyword

nonn,base

Author

Eric Angelini and Carole Dubois, Feb 24 2020

Status

approved