A279688 Numbers k such that k and 2k are anagrams in some base.

0, 8, 18, 21, 27, 32, 40, 48, 65, 66, 72, 78, 86, 96, 98, 99, 104, 108, 111, 114, 123, 133, 168, 176, 189, 190, 200, 208, 225, 240, 248, 258, 260, 264, 266, 270, 280, 288, 294, 296, 297, 312, 314, 318, 320, 330, 341, 350, 363, 380, 387, 396, 399, 408, 429, 432

Offset: 1

Author

Peter Kagey, Dec 17 2016

Keywords

• nonn
• base
• look

Examples

			a(2) = 8  because in base 5, 8  = 13_5  and 16 = 31_5.
a(3) = 18 because in base 4, 18 = 102_4 and 36 = 210_4.
		

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A023094.

Programs

Mathematica

fQ[n_] := Block[{b = 2}, While[ 2b < n +3 && Sort[ IntegerDigits[n, b]] != Sort[ IntegerDigits[ 2n, b]], b++]; 2b < n +3]; fQ[0] = True; Select[Range[0, 435], fQ] (* Robert G. Wilson v, Dec 21 2016 *)

PARI

isok(n) = if (n==0, 1, for (b=2, n, if (vecsort(digits(n,b)) == vecsort(digits(2*n,b)), return(1))); 0); \\ Michel Marcus, Dec 17 2016