The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A045560

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A045560

Numbers whose factorial has '48' as its final two digits before the trailing zeros.
(history; published version)

#13 by Susanna Cuyler at Tue Jun 22 01:02:28 EDT 2021

STATUS

proposed

approved

#12 by Jon E. Schoenfield at Tue Jun 22 00:09:17 EDT 2021

STATUS

editing

proposed

#11 by Jon E. Schoenfield at Tue Jun 22 00:09:15 EDT 2021

NAME

Numbers n such that whose factorial has '48' as its final 2 nonzero two digits of n! are '48'before the trailing zeros.

STATUS

approved

editing

#10 by Charles R Greathouse IV at Wed Oct 22 13:36:54 EDT 2014

STATUS

editing

approved

#9 by Charles R Greathouse IV at Wed Oct 22 13:26:36 EDT 2014

LINKS

Charles R Greathouse IV, <a href="/A045560/b045560.txt">Table of n, a(n) for n = 1..10000</a>

PROG

(PARI) last(n, k)=if(n*8\9-1<k, n=n!; return(n/10^valuation(n, 10)%10^k)); my(m=Mod(1, 5^k)); for(i=2, n, m*=i/10^valuation(i, 5)); lift(chinese(m, Mod(0, 2^k))) \\ Gives the last k decimal digits of n!.

is(n)=last(n, 2)==48 \\ Charles R Greathouse IV, Oct 22 2014

(PARI) is(n)=my(m=Mod(1, 25)); for(i=2, n, m*=i/10^valuation(i, 5)); m==48 \\ Charles R Greathouse IV, Oct 22 2014

(PARI) v=List(); m=Mod(1, 25); for(n=2, 1e6, m*=n/10^valuation(n, 5); if(m==48, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

KEYWORD

nonn,base

STATUS

approved

editing

#8 by N. J. A. Sloane at Sun May 19 12:18:44 EDT 2013

AUTHOR

Jeff Burch (gburch(AT)erols.com)

Jeff Burch

Discussion

Sun May 19

12:18

OEIS Server: https://oeis.org/edit/global/1922

#7 by Russ Cox at Sun Jul 10 18:42:54 EDT 2011

LINKS

<a href="/Sindx_index/Fi.html#final">Index entries for sequences related to final digits of numbers</a>

Discussion

Sun Jul 10

18:42

OEIS Server: https://oeis.org/edit/global/40

#6 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

<a href="/Sindx_Fi.html#final">Index entries for sequences related to final digits of numbers</a>

KEYWORD

nonn,new

nonn

#5 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

LINKS

<a href="http://www.research.att.com/~njas/sequences/Sindx_Fi.html#final">Index entries for sequences related to final digits of numbers</a>

KEYWORD

nonn,new

nonn

#4 by N. J. A. Sloane at Sun Jun 29 03:00:00 EDT 2008

OFFSET

0,1,1

KEYWORD

nonn,new

nonn