A290869 Numbers that are repdigits with length > 2 in more than two bases.

4095, 32767, 65535, 67053, 262143, 265720, 531440, 1048575, 2097151, 4381419, 5592405, 7174453, 9808617, 11184810, 13938267, 14348906, 16777215, 19617234, 21523360, 29425851, 39234468, 43046720, 48686547, 49043085, 58851702, 61035156, 68660319, 71270178

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

Subsequence of A167783.

Sequence in context: A359084 A043452 A261593 * A075952 A075957 A075953

Adjacent sequences: A290866 A290867 A290868 * A290870 A290871 A290872

Keyword

nonn,base

Author

Michel Marcus, Aug 13 2017

Extensions

More terms from Giovanni Resta, Aug 13 2017

Status

approved