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

Author

Andrey Zabolotskiy and Altug Alkan, Sep 26 2016

Keywords

• nonn
• base
• more

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, ...

Examples

			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.

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.