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.

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A136754 Leading digit of n! in base 3.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			a(10) = 2 as 10! = 20211100210000_3 which has leading digit 2. - _David A. Corneth_, Jan 15 2021
		

Crossrefs

Programs

  • Mathematica
    Table[First[IntegerDigits[n!,3]],{n,0,87}] (* Stefano Spezia, Aug 25 2022 *)
  • PARI
    a(n, {b = 3}) = my(f = n!); f \ b^logint(f, b) \\ David A. Corneth, Jan 10 2021

Extensions

Missing a(0)=1 inserted by David A. Corneth, Jan 10 2021

A136758 a(n) = leading digit of n! in base 7.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			a(10) = 4 as 10! = 42562410_7 which has leading digit 4. - _David A. Corneth_, Jan 15 2021
		

Crossrefs

Programs

A136759 a(n) = leading digit of n! in base 8.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Crossrefs

Programs

  • Maple
    f:= proc(n) local v; v:= n!; floor(v/8^floor(ilog2(v)/3)) end proc:
    map(f, [$1..100]); # Robert Israel, Jun 07 2018
  • Mathematica
    Array[IntegerDigits[#!, 8][[1]]&, 100, 0] (* Vincenzo Librandi, Jun 07 2018 *)
  • PARI
    a(n) = digits(n!, 8)[1]; \\ Michel Marcus, Jan 27 2015

A136760 a(n) = leading digit of n! in base 9.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			a(10) = 6 as 10! = 6740700_9 which has leading digit 6. - _David A. Corneth_, Jan 15 2021
		

Crossrefs

Programs

A136761 a(n) = leading digit of n! in base 11.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			a(10) = 2 as 10! = 20594010_11 which has leading digit 2. - _David A. Corneth_, Jan 15 2021
		

Crossrefs

Programs

A136762 Leading digit of n! in base 12.

Original entry on oeis.org

1, 1, 2, 6, 2, 10, 5, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 7, 1, 1, 3, 6, 1, 2, 5, 11, 2, 5, 1, 2, 7, 1, 4, 1, 3, 11, 2, 9, 2, 9, 2, 9, 2, 10, 3, 1, 4, 1, 6, 2, 9, 3, 1, 6, 2, 11, 4, 1, 9, 4, 1, 9, 4, 1, 10, 4, 2, 1, 6, 3, 1, 9, 4, 2, 1, 8, 4, 2, 1, 9, 5, 3, 1, 1, 7, 4, 2, 1, 1, 8, 5, 3, 2, 1, 11, 7, 5, 3
Offset: 0

Views

Author

Carl R. White, Jan 21 2008

Keywords

Crossrefs

Programs

  • Mathematica
    f[n_]:=First[IntegerDigits[n!,12]]; lst={};Do[AppendTo[lst,f[n]],{n,0,2*5!}];lst (* Vladimir Joseph Stephan Orlovsky, Jun 14 2009 *)
    a136762[n_Integer] := First[Select[IntegerDigits[n!, 12], # > 0 &]]; a136762 /@ Range[0, 144] (* Michael De Vlieger, Aug 13 2014 *)

A136763 a(n) = leading digit of n! in base 13.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			a(10) = 9 as 10! = 9100926_13 which has leading digit 9. - _David A. Corneth_, Jan 15 2021
		

Crossrefs

Programs

  • Mathematica
    Table[First[IntegerDigits[n!,13]],{n,0,100}] (* Harvey P. Dale, Dec 20 2015 *)
  • PARI
    a(n) = digits(n!, 13)[1]; \\ Michel Marcus, Jan 27 2015

A136766 a(n) = leading digit of n! in base 16.

Original entry on oeis.org

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

Views

Author

Carl R. White, Jan 21 2008

Keywords

Examples

			For n=5, 5! = 5*4*3*2*1 = 120 in base 10, which is 78 in hexadecimal (7*16 + 8*1), so a(5) = 7. - _Michael B. Porter_, Sep 20 2016
		

Crossrefs

Programs

  • Mathematica
    Array[ IntegerDigits[#!, 16][[1]] &, 1001, 0] (* Robert G. Wilson v, Sep 20 2016 *)
    Table[Floor[#/16^Floor@ Log[16, #]] &[n!], {n, 0, 98}] (* Michael De Vlieger, Sep 20 2016 *)
  • PARI
    a(n) = digits(n!, 16)[1]; \\ Michel Marcus, Jan 27 2015

A018799 Smallest nonnegative integer m such that m! begins with n in base 10.

Original entry on oeis.org

0, 2, 9, 8, 7, 3, 6, 14, 96, 27, 22, 5, 15, 42, 25, 89, 69, 76, 63, 16, 87, 113, 54, 4, 23, 30, 205, 85, 34, 28, 62, 164, 41, 245, 17, 9, 36, 128, 11, 8, 185, 53, 351, 73, 369, 118, 12, 265, 129, 7, 21, 38, 235, 66, 46, 258, 81, 597, 279, 43, 72, 13, 559, 18, 203, 120, 311
Offset: 1

Views

Author

Keywords

Comments

Record high values are m = 0, 2, 9, 14, 96, 113, 205, 245, 351, 369, 597, ... (see A279089); these occur, respectively, at n = 1, 2, 3, 8, 9, 22, 27, 34, 43, 45, 58, ... (see A279090). - Jon E. Schoenfield, Jan 30 2017
The existence of such m for each n was proven by Maxfield in 1970. The first 999 terms of this sequence were calculated by Southard in 1983. - Amiram Eldar, Dec 18 2018

Examples

			Since no factorial below 96! ~ 9.91*10^149 starts with 9, we have a(9) = 96. Similarly, 16 first appears as the leading digits of 89! ~ 1.65*10^136 and hence a(16) = 89. - _Lekraj Beedassy_, Oct 31 2010 and _Robert G. Wilson v_, Nov 05 2010
		

Crossrefs

Cf. A018854.
Apart from leading term, identical to A076219.

Programs

  • Mathematica
    f[n_] := Block[{k = 0, m}, While[ m = Max[0, Floor@ Log[10, k! ] - Floor@ Log[10, n]]; (k! - Mod[k!, 10^m])/10^m != n, k++ ]; k]; Array[f, 67] (* Robert G. Wilson v, Nov 05 2010 *)
  • PARI
    A018799(n)={ local( F=1,k=0 ); while( F\1!=n, F*=k++; while( F>=n+1, F/=10)); k} \\ M. F. Hasler, Feb 01 2009

A136755 a(n) = leading digit of n! in base 4.

Original entry on oeis.org

1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 1, 2, 3, 1, 2, 3, 1, 3, 1, 3, 1, 3, 1, 1, 2, 1, 3, 2, 1, 3, 2, 1, 1, 3, 2, 1, 1, 1, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 1, 1, 1, 2, 2, 3, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 2, 1
Offset: 0

Views

Author

Carl R. White, Jan 21 2008

Keywords

Crossrefs

Programs

Previous Showing 11-20 of 29 results. Next