

A134846


Smallest number k containing no zero digit such that k^2 contains exactly n zeros.


10



32, 245, 448, 3747, 24495, 62498, 248998, 2449552, 6393747, 6244998, 244949995, 498998998, 2449489753, 24498999998, 28284271249, 248997999998, 498998999999, 4989989999997, 24899979999998
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OFFSET

1,1


COMMENTS

The corresponding squares are in A134847.
Browkin (see link, p. 29) gives a number without zero digits whose square has 26 zeros: 4472135954999579392819^2 = 20000000000000000000005837591200400708766761. However, he does not claim that it is the smallest such number, so a(26) <= 4472135954999579392819.
Indeed, there are much smaller candidates for a(26), such as 489899998999999999. We also have a(20) <= 49899989999999 and a(21) <= 498998998999998.  Giovanni Resta, Jun 28 2019


LINKS

Table of n, a(n) for n=1..19.
Jerzy Browkin, Groebner basis (in Polish)


EXAMPLE

a(1) = 32 because 32 is the smallest number without zero digits whose square has exactly one zero: 1024.


CROSSREFS

Cf. A134843, A134844, A134845, A134847.
Sequence in context: A096960 A231304 A269079 * A066392 A300565 A231801
Adjacent sequences: A134843 A134844 A134845 * A134847 A134848 A134849


KEYWORD

nonn,base,more


AUTHOR

Artur Jasinski, Nov 13 2007


EXTENSIONS

Edited and a(11), a(12), a(13) added by Klaus Brockhaus, Nov 20 2007
a(14)a(15) from Lars Blomberg, Jun 25 2011
a(16)a(19) from Giovanni Resta, Jun 28 2019


STATUS

approved



