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.

Showing 1-8 of 8 results.

A319803 a(n) = A319651(n) + A038574(n).

Original entry on oeis.org

0, 2, 4, 4, 8, 12, 8, 12, 16, 10, 16, 26, 16, 26, 36, 26, 36, 42, 20, 26, 32, 26, 36, 42, 32, 42, 52, 28, 40, 68, 40, 52, 80, 68, 80, 92, 40, 52, 80, 52, 80, 108, 80, 108, 120, 68, 80, 92, 80, 108, 120, 92, 120, 132, 56, 68, 80, 68, 80, 92, 80, 92, 104, 68, 80, 92, 80, 108, 120, 92, 120, 132, 80, 92
Offset: 0

Views

Author

Seiichi Manyama, Sep 28 2018

Keywords

Comments

This sequence is different from A055946.

Crossrefs

Base b: A319785 (b=2), this sequence (b=3), A319804 (b=4), A319805 (b=5), A319806 (b=6), A319807 (b=7), A319808 (b=8), A319747 (b=9), A052008 (b=10).

Programs

  • Mathematica
    Table[FromDigits[Reverse[#], 3] + FromDigits[#, 3] & [Sort[IntegerDigits[n, 3]]], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = my(nd=digits(n, 3)); fromdigits(vecsort(nd), 3) + fromdigits(vecsort(nd,,4), 3); \\ Michel Marcus, Sep 28 2018

A319722 Write n in 5-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 11, 16, 21, 10, 11, 12, 17, 22, 15, 16, 17, 18, 23, 20, 21, 22, 23, 24, 25, 30, 55, 80, 105, 30, 31, 56, 81, 106, 55, 56, 61, 86, 111, 80, 81, 86, 91, 116, 105, 106, 111, 116, 121, 50, 55, 60, 85, 110, 55, 56, 61, 86, 111, 60, 61, 62, 87, 112, 85
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), this sequence (b=5), A319723 (b=6), A319724 (b=7), A319725 (b=8), A319726 (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[ReverseSort[IntegerDigits[n, 5]], 5], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 5), , 4), 5); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(5, 100)
    

Formula

n <= a(n) < 5n. - Charles R Greathouse IV, Aug 07 2024

A319723 Write n in 6-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 13, 19, 25, 31, 12, 13, 14, 20, 26, 32, 18, 19, 20, 21, 27, 33, 24, 25, 26, 27, 28, 34, 30, 31, 32, 33, 34, 35, 36, 42, 78, 114, 150, 186, 42, 43, 79, 115, 151, 187, 78, 79, 85, 121, 157, 193, 114, 115, 121, 127, 163, 199, 150, 151, 157, 163
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), A319722 (b=5), this sequence (b=6), A319724 (b=7), A319725 (b=8), A319726 (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[ReverseSort[IntegerDigits[n, 6]], 6], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 6), , 4), 6); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(6, 100)
    

Formula

n <= a(n) < 6n. - Charles R Greathouse IV, Aug 07 2024

A319724 Write n in 7-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 15, 22, 29, 36, 43, 14, 15, 16, 23, 30, 37, 44, 21, 22, 23, 24, 31, 38, 45, 28, 29, 30, 31, 32, 39, 46, 35, 36, 37, 38, 39, 40, 47, 42, 43, 44, 45, 46, 47, 48, 49, 56, 105, 154, 203, 252, 301, 56, 57, 106, 155, 204, 253, 302, 105, 106, 113, 162
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), A319722 (b=5), A319723 (b=6), this sequence (b=7), A319725 (b=8), A319726 (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[ReverseSort[IntegerDigits[n, 7]], 7], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 7), , 4), 7); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(7, 100)
    

Formula

n <= a(n) < 7n. - Charles R Greathouse IV, Aug 07 2024

A319726 Write n in 9-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 28, 37, 46, 55, 64, 73, 18, 19, 20, 29, 38, 47, 56, 65, 74, 27, 28, 29, 30, 39, 48, 57, 66, 75, 36, 37, 38, 39, 40, 49, 58, 67, 76, 45, 46, 47, 48, 49, 50, 59, 68, 77, 54, 55, 56, 57, 58, 59, 60, 69, 78, 63, 64, 65, 66, 67, 68, 69
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), A319722 (b=5), A319723 (b=6), A319724 (b=7), A319725 (b=8), this sequence (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[Reverse[Sort[IntegerDigits[n,9]]],9],{n,0,70}] (* Harvey P. Dale, Oct 26 2022 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 9), , 4), 9); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(9, 100)
    

Formula

n <= a(n) < 9n. - Charles R Greathouse IV, Aug 07 2024

A319720 Write n in 4-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 9, 13, 8, 9, 10, 14, 12, 13, 14, 15, 16, 20, 36, 52, 20, 21, 37, 53, 36, 37, 41, 57, 52, 53, 57, 61, 32, 36, 40, 56, 36, 37, 41, 57, 40, 41, 42, 58, 56, 57, 58, 62, 48, 52, 56, 60, 52, 53, 57, 61, 56, 57, 58, 62, 60, 61, 62, 63, 64, 80, 144, 208, 80, 84
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), this sequence (b=4), A319722 (b=5), A319723 (b=6), A319724 (b=7), A319725 (b=8), A319726 (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[ReverseSort[IntegerDigits[n, 4]], 4], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 4), , 4), 4); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(4, 100)
    

Formula

n <= a(n) < 4n. - Charles R Greathouse IV, Aug 07 2024

A319725 Write n in 8-ary, sort digits into decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 17, 25, 33, 41, 49, 57, 16, 17, 18, 26, 34, 42, 50, 58, 24, 25, 26, 27, 35, 43, 51, 59, 32, 33, 34, 35, 36, 44, 52, 60, 40, 41, 42, 43, 44, 45, 53, 61, 48, 49, 50, 51, 52, 53, 54, 62, 56, 57, 58, 59, 60, 61, 62, 63, 64, 72, 136, 200, 264
Offset: 0

Views

Author

Seiichi Manyama, Sep 26 2018

Keywords

Crossrefs

b-ary: A073138 (b=2), A319651 (b=3), A319720 (b=4), A319722 (b=5), A319723 (b=6), A319724 (b=7), this sequence (b=8), A319726 (b=9), A004186 (b=10).

Programs

  • Mathematica
    Table[FromDigits[ReverseSort[IntegerDigits[n, 8]], 8], {n, 0, 100}] (* Paolo Xausa, Aug 07 2024 *)
  • PARI
    a(n) = fromdigits(vecsort(digits(n, 8), , 4), 8); \\ Michel Marcus, Sep 26 2018
  • Ruby
    def A(k, n)
      (0..n).map{|i| i.to_s(k).split('').sort.reverse.join.to_i(k)}
    end
    p A(8, 100)
    

Formula

n <= a(n) < 8n. - Charles R Greathouse IV, Aug 07 2024

A351988 In the factorial base expansion of n, arrange digits in decreasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 8, 8, 9, 14, 15, 12, 14, 14, 15, 16, 17, 18, 20, 20, 21, 22, 23, 24, 30, 30, 32, 54, 56, 30, 32, 32, 33, 56, 57, 54, 56, 56, 57, 62, 63, 78, 80, 80, 81, 86, 87, 48, 54, 54, 56, 60, 62, 54, 56, 56, 57, 62, 63, 60, 62, 62, 63, 64, 65, 84, 86
Offset: 0

Views

Author

Rémy Sigrist, Feb 27 2022

Keywords

Comments

This sequence is to factorial base what A004186 is to decimal base.

Examples

			For n = 1664:
- the factorial base expansion of 1664 is "214110",
- arranging these digits in decreasing order gives "421110",
- so a(1664) = 4*6! + 2*5! + 1*4! + 1*3! + 1*2! + 0*1! = 3152.
		

Crossrefs

Cf. A004186 (decimal analog), A073138 (binary analog), A108731, A319651 (ternary analog), A351987.

Programs

  • Mathematica
    max = 5; b = MixedRadix[Range[max, 2, -1]]; a[n_] := FromDigits[Sort[IntegerDigits[n, b], Greater], b]; Array[a, max!, 0] (* Amiram Eldar, Feb 28 2022 *)
  • PARI
    a(n) = { my (dd=[]); for (r=2, oo, if (n==0, dd = vecsort(dd); return (sum(k=1, #dd, dd[k]*k!)), dd = concat(dd, n%r); n\=r)) }

Formula

a(a(n)) = a(n).
a(n) >= n with equality iff n belongs to A351987.
Showing 1-8 of 8 results.