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A257785 Numbers that are Belgian-k for exactly one k. 4
0, 47, 49, 59, 65, 68, 76, 78, 79, 85, 87, 89, 95, 96, 98, 167, 177, 187, 193, 194, 239, 267, 268, 269, 286, 287, 293, 298, 299, 338, 349, 359, 367, 379, 394, 397, 398, 418, 437, 438, 458, 478, 479, 492, 497, 498, 499, 507, 528, 529, 536, 547, 548, 560, 568 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A106039 for definition of Belgian-k numbers;

A257773(a(n)) = 1;

A257778(a(n)) = A257779(a(n)).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

Let B(n) = A257778(a(n)), the singleton of a(n)-th row in A257770:

.   n |  a(n) | B(n)        n |  a(n) | B(n)         n |  a(n) | B(n)

.  ---+-------+-----     -----+-------+-----     ------+-------+-----

.   1 |     0 |   0       100 |   763 |   4       1000 |  6702 |   6

.   2 |    47 |   3       101 |   766 |   6       1001 |  6706 |   5

.   3 |    49 |   6       102 |   768 |   5       1002 |  6709 |   8

.   4 |    59 |   3       103 |   769 |   8       1003 |  6719 |   3

.   5 |    65 |   4       104 |   779 |   6       1004 |  6725 |   5

.   6 |    68 |   6       105 |   781 |   6       1005 |  6728 |   6

.   7 |    76 |   4       106 |   785 |   5       1006 |  6730 |   4

.   8 |    78 |   3       107 |   787 |   2       1007 |  6736 |   4

.   9 |    79 |   8       108 |   788 |   6       1008 |  6742 |   3

.  10 |    85 |   7       109 |   789 |   6       1009 |  6747 |   3

.  11 |    87 |   4       110 |   790 |   6       1010 |  6748 |   6

.  12 |    89 |   4       111 |   793 |   7       1011 |  6752 |   6

.  13 |    95 |   2       112 |   794 |   7       1012 |  6753 |   6

.  14 |    96 |   6       113 |   795 |   2       1013 |  6755 |   3

.  15 |    98 |   4       114 |   796 |   4       1014 |  6756 |   6

.  16 |   167 |   6       115 |   797 |   8       1015 |  6758 |   6

.  17 |   177 |   4       116 |   798 |   6       1016 |  6766 |   3

.  18 |   187 |   2       117 |   799 |   8       1017 |  6768 |   5

.  19 |   193 |   1       118 |   805 |   4       1018 |  6770 |   4

.  20 |   194 |   2       119 |   807 |   4       1019 |  6772 |   5  .

PROG

(Haskell)

a257785 n = a257785_list !! (n-1)

a257785_list = filter ((== 1) . a257773) [0..]

CROSSREFS

Cf. A257770, A257773, A007088, A257778, A257779.

Sequence in context: A249372 A042103 A084366 * A234023 A128940 A243431

Adjacent sequences:  A257782 A257783 A257784 * A257786 A257787 A257788

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 08 2015

STATUS

approved

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Last modified March 5 16:55 EST 2021. Contains 341827 sequences. (Running on oeis4.)