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 1-10 of 15 results. Next

A027869 Number of 0's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 1, 2, 2, 1, 2, 2, 4, 4, 2, 4, 4, 4, 5, 6, 7, 7, 8, 5, 6, 9, 8, 9, 10, 7, 9, 7, 10, 8, 11, 9, 10, 12, 16, 12, 9, 15, 13, 13, 12, 13, 16, 11, 14, 14, 19, 18, 18, 17, 18, 18, 17, 20, 17, 19, 19, 26, 20, 21, 20, 20, 23, 22, 25, 21, 20, 25, 23, 35
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Count[IntegerDigits[n!], 0], {n, 0, 100}] (* T. D. Noe, Apr 10 2012 *)
    DigitCount[Range[0,80]!,10,0] (* Harvey P. Dale, Jul 08 2020 *)
  • PARI
    a(n)=my(d=digits(n!)); sum(i=1,#d,d[i]==0) \\ Charles R Greathouse IV, Jul 06 2017
    
  • Python
    from math import factorial
    def a(n): return str(factorial(n)).count('0')
    print([a(n) for n in range(74)]) # Michael S. Branicky, Jan 11 2022

Formula

a(n) = A034886(n) - (A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008
A027868(n) <= a(n). - Reinhard Zumkeller, Jan 27 2008
Conjecture: a(n) ~ (9*A027868(n) + A034886(n))/10. This formula is based on the assumption that the digits other than trailing zeros are uniformly randomly distributed. - Nicolas Bělohoubek, Jan 11 2022

A137580 Number of distinct digits in decimal representation of n!.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 3, 3, 4, 5, 5, 6, 6, 5, 6, 7, 5, 9, 8, 8, 9, 7, 7, 10, 9, 8, 9, 10, 8, 9, 9, 10, 9, 10, 10, 10, 10, 10, 9, 10, 10, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
Offset: 0

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Author

Reinhard Zumkeller, Jan 27 2008

Keywords

Examples

			n=12: 12! = 479001600 => a(12) = #{0,1,4,6,7,9} = 6.
		

Crossrefs

Programs

  • Haskell
    import Data.List (nub, sort)
    a137580 = length . nub . show . a000142
    -- Reinhard Zumkeller, Apr 08 2012
    
  • Mathematica
    Map[Length[Union[IntegerDigits[#]]] &, Table[n!, {n, 0, 79}]] (* Geoffrey Critzer, May 25 2013 *)
  • PARI
    A137580(n)=#Set(digits(n!)) \\ M. F. Hasler, May 04 2015

Formula

a(n) = A043537(A000142(n)).
a(n) < 10 iff A137579(n) = 0.
a(A182049(n)) < 10. - Reinhard Zumkeller, Apr 08 2012

A079692 Number of 7's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 2, 2, 1, 1, 3, 0, 1, 2, 6, 2, 1, 0, 0, 1, 1, 3, 0, 4, 1, 1, 2, 2, 4, 3, 4, 4, 4, 3, 3, 4, 4, 4, 1, 2, 8, 5, 5, 3, 8, 5, 7, 4, 9, 4, 4, 7, 7, 6, 8, 8, 3, 9, 8, 6, 8, 8, 9, 10, 12, 7, 7, 9, 9, 7, 10, 10, 9, 14, 11, 12, 9, 7, 13, 17, 2, 11, 12, 19, 15, 12, 10, 15, 15, 16, 19, 7, 7, 12
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> numboccur(7, convert(n!, base, 10)):
    seq(a(n), n=0..101);  # Alois P. Heinz, Apr 26 2021
  • PARI
    a(n) = #select(x->(x==7), digits(n!)); \\ Michel Marcus, Apr 26 2021

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

Extensions

a(78)-a(79) corrected by Georg Fischer, Apr 26 2021

A079680 Number of 1's in n!.

Original entry on oeis.org

1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 3, 1, 3, 2, 1, 1, 4, 3, 3, 4, 4, 3, 2, 5, 7, 2, 4, 4, 4, 7, 3, 6, 6, 6, 4, 6, 7, 4, 10, 4, 5, 7, 10, 3, 2, 5, 5, 4, 7, 10, 6, 8, 3, 8, 9, 12, 5, 5, 8, 11, 9, 7, 6, 6, 16, 13, 9, 7, 7, 11, 15, 8, 9, 13, 10, 15, 13, 8, 14, 14, 12, 11, 12, 13, 16, 11
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Formula

a(n) = A034886(n) - (A027869(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

A079684 Number of 3's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 2, 0, 1, 2, 1, 1, 0, 0, 1, 5, 3, 2, 1, 3, 3, 2, 1, 7, 2, 3, 7, 4, 5, 1, 5, 3, 5, 3, 9, 3, 5, 1, 5, 7, 6, 6, 6, 4, 9, 8, 5, 3, 4, 5, 8, 8, 4, 8, 5, 9, 7, 7, 6, 9, 10, 5, 7, 8, 6, 10, 7, 11, 7, 9, 10, 8, 8, 15, 10, 13, 8, 10, 13, 8, 12, 10, 6, 18, 12, 12, 15, 9, 12
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    DigitCount[Range[0,100]!,10,3] (* Harvey P. Dale, Jul 04 2014 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

Extensions

Corrected by Jason Earls, Jul 06 2003

A079688 Number of 4's in n!.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 2, 2, 3, 1, 2, 4, 2, 3, 2, 4, 3, 1, 1, 0, 3, 4, 3, 3, 3, 3, 3, 4, 3, 6, 2, 5, 4, 3, 3, 4, 3, 7, 3, 5, 7, 6, 6, 13, 8, 8, 7, 10, 4, 4, 8, 10, 8, 16, 10, 7, 13, 6, 5, 10, 7, 7, 13, 11, 11, 10, 4, 13, 13, 16, 10, 8, 15, 14, 10, 18, 6, 13, 12, 17, 12
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    DigitCount[#,10,4]&/@(Range[0,100]!) (* Harvey P. Dale, Jul 30 2015 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

A079690 Number of 5's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 0, 1, 0, 2, 0, 3, 3, 2, 2, 2, 4, 3, 1, 2, 2, 2, 2, 5, 1, 2, 5, 6, 5, 7, 5, 5, 8, 5, 6, 5, 2, 4, 7, 3, 3, 11, 5, 6, 5, 5, 3, 7, 6, 4, 7, 10, 3, 7, 8, 5, 10, 7, 3, 7, 13, 9, 10, 6, 9, 7, 14, 13, 1, 12, 8, 13, 13, 11, 10, 10, 12, 17, 17, 14, 15, 12
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    DigitCount[#,10,5]&/@(Range[0,100]!) (* Harvey P. Dale, Sep 17 2016 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

A079691 Number of 6's in n!.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 2, 0, 2, 1, 1, 2, 0, 2, 3, 2, 0, 4, 3, 2, 3, 3, 2, 5, 3, 4, 7, 2, 3, 5, 2, 3, 6, 5, 6, 5, 8, 4, 7, 6, 6, 9, 5, 8, 7, 3, 9, 6, 7, 4, 6, 8, 6, 6, 11, 6, 8, 8, 11, 6, 4, 11, 11, 10, 6, 5, 9, 8, 9, 8, 11, 10, 8, 11, 12, 13, 9, 11, 7, 12, 15, 15, 17, 8, 11, 16, 11
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Table[DigitCount[n!,10,6],{n,0,100}] (* Harvey P. Dale, Aug 08 2023 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

A079693 Number of 8's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 1, 0, 1, 2, 1, 4, 2, 1, 2, 1, 0, 1, 4, 1, 2, 1, 6, 4, 2, 5, 6, 2, 8, 2, 1, 3, 2, 0, 7, 4, 2, 4, 2, 9, 3, 7, 4, 4, 7, 5, 5, 9, 8, 9, 4, 11, 7, 10, 9, 4, 11, 7, 7, 12, 7, 9, 9, 7, 8, 14, 18, 15, 9, 9, 10, 8, 18, 12, 14, 13, 8, 10, 8, 12, 5, 8, 8, 18, 10, 14, 9, 11, 12, 16
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Table[DigitCount[n!,10,8],{n,0,100}] (* Harvey P. Dale, May 06 2016 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

A079694 Number of 9's in n!.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 0, 1, 0, 2, 1, 0, 0, 1, 3, 0, 1, 2, 2, 1, 1, 0, 4, 2, 1, 2, 2, 5, 3, 7, 4, 1, 5, 5, 0, 4, 2, 2, 4, 6, 7, 3, 2, 2, 3, 3, 6, 4, 6, 6, 5, 6, 8, 6, 7, 6, 7, 5, 6, 6, 8, 8, 7, 12, 5, 7, 5, 7, 10, 12, 7, 6, 9, 5, 12, 13, 12, 10, 9, 9, 10, 13, 18, 14, 12, 7, 7, 7, 15, 20, 16
Offset: 0

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Crossrefs

Programs

  • Mathematica
    DigitCount[#,10,9]&/@(Range[0,100]!) (* Harvey P. Dale, Dec 12 2013 *)

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079714(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n)). - Reinhard Zumkeller, Jan 27 2008
Showing 1-10 of 15 results. Next