

A220289


Smallest composite integer in base n which remains composite after altering any one or two digits.


1




OFFSET

2,1


COMMENTS

Unlike A133219, changing the most significant digit to 0 is disallowed.


LINKS

Table of n, a(n) for n=2..10.
Witold Jarnicki and Maciej Zenczykowski, On a property of the number 977731833235239280, arXiv:0709.3361 [math.NT], 2007.


EXAMPLE

Expressed in base 10, the terms from n=2 to 9 are: 84, 1953, 28268, 1401590, 273241578, 77478704205, 1878528135128, 48398467146642.  edited by Michel Marcus, Sep 27 2014


CROSSREFS

Cf. A133219.
Sequence in context: A234035 A330519 A066354 * A133219 A306515 A306517
Adjacent sequences: A220286 A220287 A220288 * A220290 A220291 A220292


KEYWORD

base,nonn,more


AUTHOR

Michel Marcus, Dec 09 2012


EXTENSIONS

Typo for a(10) corrected by Michel Marcus, Sep 27 2014


STATUS

approved



