A097261 - OEIS

%I #16 Sep 08 2022 08:45:14

%S 0,14,210,224,3150,3164,3360,3374,47250,47264,47460,47474,50400,50414,

%T 50610,50624,708750,708764,708960,708974,711900,711914,712110,712124,

%U 756000,756014,756210,756224,759150,759164,759360,759374,10631250

%N Numbers whose set of base 15 digits is {0,E}, where E base 15 = 14 base 10.

%C n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a power of 15 for every i.

%H Vincenzo Librandi, <a href="/A097261/b097261.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = 14*A033051(n).

%F a(2n) = 15*a(n), a(2n+1) = a(2n)+14.

%t f[n_] := FromDigits[ IntegerDigits[n, 2] /. {1 -> 14}, 15]; Array[f, 33, 0] (* or *)

%t FromDigits[#, 15] & /@ Tuples[{0, 14}, 6] (* _Harvey P. Dale_, Sep 22 2011 *) (* or much slower *)

%t fQ[n_] := Union@ Join[{0, 14}, IntegerDigits[n, 15]] == {0, 14}; Select[ Range[0, 10634414 ], fQ] (* _Robert G. Wilson v_, May 12 2012 *)

%o (Magma) [n: n in [0..4500000] | Set(IntegerToSequence(n, 15)) subset {0, 14}]; // _Vincenzo Librandi_, Jun 05 2012

%Y Cf. A001196, A005823, A097251-A097262.

%K nonn,base

%O 0,2

%A _Ray Chandler_, Aug 03 2004