A045553 Numbers whose factorial has '12' as its final two digits before the trailing zeros.

5, 14, 38, 43, 47, 50, 51, 88, 90, 111, 129, 153, 242, 254, 275, 276, 292, 367, 387, 420, 423, 436, 454, 496, 513, 530, 570, 573, 577, 581, 608, 614, 619, 633, 644, 660, 699, 710, 722, 743, 771, 787, 799, 825, 826, 837

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)==12 \\ 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==12 \\ 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==12, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

Crossrefs

Sequence in context: A054486 A072130 A196976 * A270687 A272254 A270452

Adjacent sequences: A045550 A045551 A045552 * A045554 A045555 A045556

Keyword

nonn,base

Author

Jeff Burch

Status

approved