A045557 - OEIS

A045557

Numbers whose factorial has '32' as its final two digits before the trailing zeros.

8, 19, 35, 74, 85, 97, 118, 145, 148, 180, 203, 225, 226, 270, 273, 287, 299, 306, 314, 325, 326, 337, 350, 351, 375, 376, 434, 441, 447, 457, 470, 473, 482, 509, 510, 516, 533, 544, 627, 659, 661, 666, 711, 718, 747, 806, 814, 842, 849

(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)==32 \\ 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==32 \\ 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==32, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A262713 A135027 A158916 * A289877 A089111 A127873

Adjacent sequences: A045554 A045555 A045556 * A045558 A045559 A045560

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved