A062070 Smallest base b such that the decimal digits of n interpreted as digits in base b give a square, or 0 if no such base exists.

2, 2, 0, 0, 2, 0, 0, 0, 0, 2, 4, 3, 2, 6, 5, 4, 3, 2, 8, 7, 2, 4, 7, 3, 6, 2, 5, 9, 4, 8, 3, 5, 0, 2, 4, 0, 10, 3, 0, 9, 4, 2, 0, 0, 3, 5, 0, 0, 2, 4, 5, 3, 0, 0, 9, 4, 2, 0, 0, 8, 6, 4, 0, 13, 2, 0, 5, 3, 0, 12, 7, 5, 2, 0, 3, 0, 0, 6, 4, 13, 2, 3, 0, 0, 4, 0, 0, 0, 7, 2, 4, 7, 0, 0, 5, 0, 0, 2, 0, 3, 2

Offset

0,1

Links

Felix Fröhlich, Table of n, a(n) for n = 0..10000

Example

a(13) = 6 since 13_6 = 9 = 3^2 and this is the smallest such base.

Prog

(PARI) a(n) = {for (b=2, n+2, if (issquare(fromdigits(digits(n), b)), return (b)); ); return (0); } \\ Michel Marcus, Nov 20 2017

Crossrefs

Sequence in context: A281790 A245254 A059080 * A347088 A343991 A239395

Adjacent sequences: A062067 A062068 A062069 * A062071 A062072 A062073

Keyword

base,easy,nice,nonn

Author

Erich Friedman, Jun 27 2001

Extensions

Name clarified by Felix Fröhlich and Kevin Ryde, May 17 2021

Status

approved