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

Author

Jeff Burch

Keywords

• nonn
• base

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to final digits of numbers

Programs

PARI

last(n,k)=if(n*8\9-1Charles 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

Extensions

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