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 11-14 of 14 results.

A079714 Number of 2's in n!.

Original entry on oeis.org

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

Views

Author

Cino Hilliard, Jan 31 2003

Keywords

Links

Crossrefs

Cf. A000142, A137579, A137580.
Cf. A316863.

Programs

  • Maple
    a:= n-> numboccur(2, convert(n!, base, 10)):
seq(a(n), n=0..101);  # Alois P. Heinz, Apr 26 2021
  • Mathematica
    Table[DigitCount[n!,10,2],{n,0,110}] (* Harvey P. Dale, Jun 20 2021 *)
  • PARI
    a(n) = #select(x->(x==2), digits(n!)); \\ Michel Marcus, Apr 26 2021

Formula

a(n) = A034886(n) - (A027869(n) + A079680(n) + A079684(n) + A079688(n) + A079690(n) + A079691(n) + A079692(n) + A079693(n) + A079694(n)). - Reinhard Zumkeller, Jan 27 2008

Extensions

a(36) ff. corrected by Georg Fischer, Apr 26 2021

A316868 Number of times 7 appears in decimal expansion of n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0
Offset: 0

Views

Author

Robert G. Wilson v, Jul 15 2018

Keywords

Examples

			a(0) = 0 since the decimal representation of 0 does not contain the digit 7.
a(7) = 1 since 7 appears once in the decimal expansion of 7.

Crossrefs

Cf. A043517, A043518, A043519, A043520.
Cf. A055641, A268643, A316863, A316864, A316865, A316866, A316867, A316869, A102683.
Cf. A079692.

Programs

  • Mathematica
    Array[ DigitCount[#, 10, 7] &, 105, 0]
  • PARI
    a(n) = #select(x->x==7, digits(n)); \\ Michel Marcus, Jul 20 2018

A137577 Largest of the least frequent digits in decimal representation of n!.

Original entry on oeis.org

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

Views

Author

Reinhard Zumkeller, Jan 27 2008

Keywords

Comments

A137578(n) <= a(n).

Examples

			n=10: 10! = 3628800 => a(10) = Max{1,4,5,7,9} = 9;
n=11: 11! = 39916800 => a(11) = Max{2,4,5,7} = 7.

Links

Crossrefs

Cf. A000142, A027869, A079680, A079714, A079684, A079688, A079690, A079691, A079692, A079693, A079694, A137579, A137580.

A137578 Smallest of the least frequent digits in decimal representation of n!.

Original entry on oeis.org

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

Views

Author

Reinhard Zumkeller, Jan 27 2008

Keywords

Comments

a(n) <= A137577(n).

Examples

			n=10: 10! = 3628800 => a(10) = Min{1,4,5,7,9} = 1;
n=11: 11! = 39916800 => a(11) = Min{2,4,5,7} = 2.

Links

Crossrefs

Cf. A000142, A027869, A079680, A079714, A079684, A079688, A079690, A079691, A079692, A079693, A079694, A137579, A137580.
Previous Showing 11-14 of 14 results.

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