OFFSET
1,1
COMMENTS
Most of the terms of A167783 are repdigits with length > 2 in only two bases.
For any b > 1 and k > 2, b^(4*k)-1 is a repdigit with length > 2 in bases b, b^2 and b^4; hence this sequence is infinite. - Rémy Sigrist, Aug 19 2017
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..777
Rémy Sigrist, C# program for A290869
Rémy Sigrist, C++ program for A290869
EXAMPLE
67053 is a repdigit with more than 2 digits in three bases: [31,31,31]_46, [21,21,21]_56, [3,3,3]_149.
PROG
(PARI) isok(n)=my(nb = 0); for (b=2, n-1, d = digits(n, b); if ((#d > 2) && (#Set(d) == 1), nb++); if (nb > 2, return (1)); ); return (0);
(C#) See Links section.
(C++) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Michel Marcus, Aug 13 2017
EXTENSIONS
More terms from Giovanni Resta, Aug 13 2017
STATUS
approved