A023061 Positive numbers k such that k and 2*k are anagrams in base 5 (written in base 5).

13, 130, 143, 1300, 1313, 1430, 1443, 13000, 13013, 13130, 13143, 14300, 14313, 14430, 14443, 102342, 103242, 120234, 120324, 130000, 130013, 130130, 130143, 131300, 131313, 131430, 131443, 143000, 143013, 143130, 143143, 144300, 144313

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• base

Comments

From Robert Israel, Aug 08 2018: (Start)

The concatenation of two terms is a term.

If a*10^m + b is a term, where b < (2/9)*10^m, then a*10^k+b is a term for all k > m. (End)

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2000 from Robert Israel)

Crossrefs

Cf. A007091.

Programs

Maple

f:= proc(n) local L, M;
   L:= convert(n, base, 5);
   M:= convert(2*n, base, 5);
   if sort(L) = sort(M) then add(L[i]*10^(i-1), i=1..nops(L)) else NULL fi
end proc:
map(f, [$1..10000]); # Robert Israel, Aug 08 2018

Mathematica

FromDigits[IntegerDigits[#, 5]] & /@ Select[Range[10000], SameQ @@ Sort /@ IntegerDigits[{#, 2*#}, 5] &] (* Amiram Eldar, Aug 06 2025 *)