A045563 Numbers whose factorial has '64' as its final two digits before the trailing zeros.

20, 23, 92, 99, 100, 101, 143, 156, 195, 198, 208, 219, 227, 230, 268, 280, 327, 331, 352, 355, 377, 415, 449, 497, 500, 501, 560, 568, 596, 607, 632, 653, 681, 689, 749, 761, 765, 772, 783, 794, 856, 902, 914, 932, 946, 964, 1005, 1014, 1035, 1085, 1097

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)==64 \\ 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==64 \\ 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==64, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

Crossrefs

Sequence in context: A153717 A358424 A303303 * A013339 A199360 A199585

Adjacent sequences: A045560 A045561 A045562 * A045564 A045565 A045566

Keyword

nonn,base

Author

Jeff Burch

Extensions

More terms from Robert G. Wilson v, Dec 14 2000

Status

approved