A023094 a(n) is least k such that k and 2k are anagrams in base n (written in base 10).

32, 18, 8, 350, 480, 21, 104, 125874, 40, 4147, 5712, 65, 15680, 585, 96, 833, 7776, 133, 61600, 46851, 176, 63595, 2232, 225, 106288, 122931, 280, 3857, 91948380, 341, 237184, 83853, 408, 543900, 7236, 481, 8474, 431516631, 560, 622339, 683760, 645

Offset: 3

Author

David W. Wilson

Keywords

• nonn
• base
• changed

Comments

a(n) is divisible by n-1 for all n due to the anagram property: n and 2n are congruent modulo n-1. - Peter Kagey, Dec 23 2016

Links

• Amiram Eldar, Table of n, a(n) for n = 3..174
• Mathematics Stack Exchange, Lower Bound for Anagram Sequence.

Crossrefs

Cf. A000567, A023095, A023096, A023097, A023098, A023099, A023100, A023101, A023102.

Programs

Mathematica

Table[k = 1; While[! MatchQ @@ Map[Sort@ IntegerDigits[#, n] &, k {1, 2}], k++]; k, {n, 3, 30}] (* Michael De Vlieger, Dec 17 2016 *)

PARI

a(n) = {my(k=1); while (vecsort(digits(k,n)) != vecsort(digits(2*k,n)), k++); k;} \\ Michel Marcus, Dec 17 2016

Formula

a(3n-1) = A000567(n). - Peter Kagey, Dec 16 2016