OFFSET
0,2
COMMENTS
n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a power of 12 for every i.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = 11*A033048(n).
a(2n) = 12*a(n), a(2n+1) = a(2n)+11.
MATHEMATICA
f[n_] := FromDigits[ IntegerDigits[n, 2] /. {1 -> 11}, 12]; Array[f, 33, 0] (* or much slower *)
fQ[n_] := Union@ Join[{0, 11}, IntegerDigits[n, 12]] == {0, 11}; Select[ Range[0, 27370162], fQ] (* Robert G. Wilson v, May 12 2012 *)
FromDigits[#, 12]&/@Tuples[{0, 11}, 6] (* Vincenzo Librandi, May 26 2012 *)
PROG
(Magma) [n: n in [0..2800000] | Set(IntegerToSequence(n, 12)) subset {0, 11}]; // Vincenzo Librandi, May 26 2012
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Ray Chandler, Aug 03 2004
STATUS
approved