A277056 Least k such that any sufficiently long repunit multiplied by k is a pandigital number in numerical base n.

2, 5, 7, 34, 195, 727, 3724, 9124, 92115, 338161, 2780514, 6871290, 99000993

Offset

2,1

Comments

Trailing terms of rows of A277055.

Written in base n, the terms read: 10, 12, 13, 114, 523, 2056, 7214, 13457, 92115, 21107A, B21116, 156776A, D211117, ...

Links

Table of n, a(n) for n=2..14.

Formula

Conjecture: for even n>4, a(n) = (n-2)*n^(n/2-1) + n^(n/2-2) + (n^(n/2)-1)/(n-1) + n/2 - 1.

Example

Any binary repunit multiplied by 2 is a binary pandigital, so a(2)=2 (10 in binary).
k-th decimal repunit for k>4 multiplied by 92115 gives a decimal pandigital number (see A277054) with no number less than 92115 having the same property, so a(10)=92115.

Crossrefs

Cf. A002275, A171102, A277054, A277055, A277059.

Sequence in context: A085394 A041875 A072188 * A160621 A028432 A019409

Adjacent sequences: A277053 A277054 A277055 * A277057 A277058 A277059

Keyword

nonn,base,more

Author

Andrey Zabolotskiy and Altug Alkan, Sep 26 2016

Status

approved