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A257785 Numbers that are Belgian-k for exactly one k.

%I A257785 #5 May 08 2015 16:56:13
%S A257785 0,47,49,59,65,68,76,78,79,85,87,89,95,96,98,167,177,187,193,194,239,
%T A257785 267,268,269,286,287,293,298,299,338,349,359,367,379,394,397,398,418,
%U A257785 437,438,458,478,479,492,497,498,499,507,528,529,536,547,548,560,568
%N A257785 Numbers that are Belgian-k for exactly one k.
%C A257785 See A106039 for definition of Belgian-k numbers;
%C A257785 A257773(a(n)) = 1;
%C A257785 A257778(a(n)) = A257779(a(n)).
%H A257785 Reinhard Zumkeller, <a href="/A257785/b257785.txt">Table of n, a(n) for n = 1..10000</a>
%e A257785 Let B(n) = A257778(a(n)), the singleton of a(n)-th row in A257770:
%e A257785 .   n |  a(n) | B(n)        n |  a(n) | B(n)         n |  a(n) | B(n)
%e A257785 .  ---+-------+-----     -----+-------+-----     ------+-------+-----
%e A257785 .   1 |     0 |   0       100 |   763 |   4       1000 |  6702 |   6
%e A257785 .   2 |    47 |   3       101 |   766 |   6       1001 |  6706 |   5
%e A257785 .   3 |    49 |   6       102 |   768 |   5       1002 |  6709 |   8
%e A257785 .   4 |    59 |   3       103 |   769 |   8       1003 |  6719 |   3
%e A257785 .   5 |    65 |   4       104 |   779 |   6       1004 |  6725 |   5
%e A257785 .   6 |    68 |   6       105 |   781 |   6       1005 |  6728 |   6
%e A257785 .   7 |    76 |   4       106 |   785 |   5       1006 |  6730 |   4
%e A257785 .   8 |    78 |   3       107 |   787 |   2       1007 |  6736 |   4
%e A257785 .   9 |    79 |   8       108 |   788 |   6       1008 |  6742 |   3
%e A257785 .  10 |    85 |   7       109 |   789 |   6       1009 |  6747 |   3
%e A257785 .  11 |    87 |   4       110 |   790 |   6       1010 |  6748 |   6
%e A257785 .  12 |    89 |   4       111 |   793 |   7       1011 |  6752 |   6
%e A257785 .  13 |    95 |   2       112 |   794 |   7       1012 |  6753 |   6
%e A257785 .  14 |    96 |   6       113 |   795 |   2       1013 |  6755 |   3
%e A257785 .  15 |    98 |   4       114 |   796 |   4       1014 |  6756 |   6
%e A257785 .  16 |   167 |   6       115 |   797 |   8       1015 |  6758 |   6
%e A257785 .  17 |   177 |   4       116 |   798 |   6       1016 |  6766 |   3
%e A257785 .  18 |   187 |   2       117 |   799 |   8       1017 |  6768 |   5
%e A257785 .  19 |   193 |   1       118 |   805 |   4       1018 |  6770 |   4
%e A257785 .  20 |   194 |   2       119 |   807 |   4       1019 |  6772 |   5  .
%o A257785 (Haskell)
%o A257785 a257785 n = a257785_list !! (n-1)
%o A257785 a257785_list = filter ((== 1) . a257773) [0..]
%Y A257785 Cf. A257770, A257773, A007088, A257778, A257779.
%K A257785 nonn
%O A257785 1,2
%A A257785 _Reinhard Zumkeller_, May 08 2015