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 A279688 Numbers k such that k and 2k are anagrams in some base. 3

%I

%S 0,8,18,21,27,32,40,48,65,66,72,78,86,96,98,99,104,108,111,114,123,

%T 133,168,176,189,190,200,208,225,240,248,258,260,264,266,270,280,288,

%U 294,296,297,312,314,318,320,330,341,350,363,380,387,396,399,408,429,432

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

%H Chai Wah Wu, <a href="/A279688/b279688.txt">Table of n, a(n) for n = 1..10001</a>

%e a(2) = 8 because in base 5, 8 = 13_5 and 16 = 31_5.

%e a(3) = 18 because in base 4, 18 = 102_4 and 36 = 210_4.

%t 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 *)

%o (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

%Y Cf. A023094.

%K nonn,base,look

%O 1,2

%A _Peter Kagey_, Dec 17 2016

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Last modified December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)