Voozh

A045569

Numbers whose factorial has '92' as its final two digits before the trailing zeros.

84, 91, 110, 115, 181, 189, 217, 224, 228, 302, 308, 319, 328, 353, 378, 404, 407, 435, 443, 518, 527, 539, 554, 589, 602, 605, 630, 639, 663, 668, 672, 675, 676, 713, 715, 736, 757, 775, 776, 792, 802, 808, 819

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Index entries for sequences related to final digits of numbers

MATHEMATICA

fndQ[n_]:=Module[{f=n!}, Take[Drop[IntegerDigits[f], -IntegerExponent[ f, 10]], -2] == {9, 2}]; Select[Range[5, 900], fndQ] (* Harvey P. Dale, Sep 26 2016 *)

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)==92 \\ 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==92 \\ 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==92, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A095607 A068405 A349760 * A219183 A289218 A329182

Adjacent sequences: A045566 A045567 A045568 * A045570 A045571 A045572

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved

URL: https://oeis.org/A045569

⇱ A045569 - OEIS