

A332795


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


7



1, 10, 11, 100, 21, 1000, 31, 10000, 41, 100000, 51, 1000000, 61, 10000000, 71, 100000000, 81, 2817
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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) = 245a(19)7 = 24587a(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



