A045559 - OEIS

A045559

Numbers whose factorial has '44' as its final two digits before the trailing zeros.

21, 78, 112, 134, 135, 141, 155, 182, 196, 202, 206, 259, 260, 266, 320, 323, 330, 413, 418, 422, 428, 437, 442, 463, 465, 485, 490, 517, 545, 548, 559, 566, 572, 579, 620, 623, 650, 651, 667, 680, 728, 768, 781, 820, 823, 833, 844

(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

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)==44 \\ 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==44 \\ 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==44, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A085027 A143206 A182754 * A144314 A010009 A172082

Adjacent sequences: A045556 A045557 A045558 * A045560 A045561 A045562

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved