cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-16 of 16 results.

A107043 Belgian-9 numbers.

Original entry on oeis.org

9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 25, 27, 30, 32, 33, 36, 45, 51, 54, 57, 63, 67, 69, 72, 81, 83, 90, 93, 99, 100, 101, 102, 104, 105, 108, 109, 110, 111, 115, 117, 119, 120, 121, 122, 123, 124, 126, 129, 130, 135, 139, 140, 141, 142, 144, 146, 149, 153
Offset: 1

Views

Author

Eric Angelini, Jun 07 2005

Keywords

Crossrefs

See A106039 for definition and link.
Cf. A257770.

Programs

  • Haskell
    a107043 n = a107043_list !! (n-1)
    a107043_list = filter belge9 [9..] where
       belge9 x = x == (head $ dropWhile (< x) $
                        scanl (+) 9 $ cycle (map (read . return) $ show x))
    -- Reinhard Zumkeller, May 08 2015
  • Mathematica
    belgianQ[n_, k_] := If[n < k, False, Block[{id = Join[{0}, IntegerDigits@ n]}, MemberQ[ Accumulate@ id, Mod[n - k, Plus @@ id]] ]]; Select[ Range@ 155, belgianQ[#, 9] &] (* Robert G. Wilson v, May 06 2011 *)

Extensions

Offset changed by Reinhard Zumkeller, May 08 2015

A257773 Number of numbers k, 0 <= k <= 9, such that n is a Belgian-k number.

Original entry on oeis.org

1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 10, 10, 7, 6, 4, 4, 4, 4, 3, 2, 5, 7, 5, 4, 3, 3, 3, 3, 2, 2, 4, 5, 4, 4, 2, 3, 3, 2, 2, 2, 3, 4, 4, 3, 3, 3, 2, 1, 2, 1, 2, 3, 2, 3, 3, 2, 2, 2, 2, 1, 2, 2, 3, 3, 2, 1, 2, 2, 1, 2, 2, 3, 3, 2, 2, 2, 1, 2, 1, 1, 2, 3, 2, 2, 2, 1
Offset: 0

Views

Author

Reinhard Zumkeller, May 08 2015

Keywords

Comments

See A106039 for definition of Belgian-k numbers.
row lengths in A257770;
a(A257785(n)) = 1;
For n > 1: a(A007088(n)) = 10.

Crossrefs

Programs

  • Haskell
    a257773 = length . a257770_row

A257778 Smallest k, such that n is a Belgian-k number.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 1, 0, 0, 8, 0, 0, 0, 1, 0, 2, 0, 0, 6, 5, 0, 0, 2, 0, 3, 0, 0, 4, 2, 0, 0, 1, 0, 1, 0, 0, 2, 3, 0, 6, 0, 3, 3, 0, 0, 0, 1, 4, 1, 3, 0, 5, 0, 0, 4, 4, 0, 2, 6, 3, 0, 0, 0, 3, 1, 3, 4, 0, 3, 8, 0, 0, 2, 6, 0, 7
Offset: 0

Views

Author

Reinhard Zumkeller, May 08 2015

Keywords

Comments

See A106039 for definition of Belgian-k numbers;
a(n) = A257770(n,0);
a(n) <= A257779(n); a(A257785(n)) = A257779(A257785(n));
conjecture: a(n) < 9;
a(A106039(n)) = 0; a(A257782(n)) > 0.

Crossrefs

Programs

  • Haskell
    a257778 = head . a257770_row

A257779 Largest k, such that n is a Belgian-k number.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8, 9, 8, 8, 6, 9, 8, 9, 8, 7, 9, 8, 9, 9, 6, 8, 9, 7, 5, 3, 8, 7, 8, 8, 8, 9, 6, 3, 8, 6, 5, 9, 5, 8, 9, 5, 7, 9, 6, 3, 6, 6, 8, 9, 8, 4, 6, 9, 6, 9, 7, 8, 9, 6, 8, 8, 4, 7, 3, 8, 8, 9, 4, 9, 4, 7
Offset: 0

Views

Author

Reinhard Zumkeller, May 08 2015

Keywords

Comments

See A106039 for definition of Belgian-k numbers;
a(n) = A257770(n,A257773(n));
a(n) >= A257778(n); a(A257785(n)) = A257778(A257785(n)).

Crossrefs

Programs

  • Haskell
    a257779 = last . a257770_row

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

Original entry on oeis.org

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
Offset: 1

Views

Author

Reinhard Zumkeller, May 08 2015

Keywords

Comments

See A106039 for definition of Belgian-k numbers;
A257773(a(n)) = 1;
A257778(a(n)) = A257779(a(n)).

Examples

			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  .
		

Crossrefs

Programs

  • Haskell
    a257785 n = a257785_list !! (n-1)
    a257785_list = filter ((== 1) . a257773) [0..]

A257782 Numbers that are not Belgian-0 numbers.

Original entry on oeis.org

14, 15, 16, 19, 23, 25, 28, 29, 32, 34, 37, 38, 41, 43, 46, 47, 49, 51, 52, 56, 57, 58, 59, 61, 64, 65, 67, 68, 69, 73, 74, 75, 76, 78, 79, 82, 83, 85, 86, 87, 89, 91, 92, 94, 95, 96, 97, 98, 103, 104, 105, 107, 109, 113, 115, 116, 118, 119, 122, 124, 125
Offset: 1

Views

Author

Reinhard Zumkeller, May 08 2015

Keywords

Comments

A257778(a(n)) = A257770(a(n),0) > 0.

Crossrefs

Cf. A257770, A257778, A106039 (complement).

Programs

  • Haskell
    a257782 n = a257782_list !! (n-1)
    a257782_list = filter ((> 0) . a257778) [0..]
Previous Showing 11-16 of 16 results.