VOOZH about

URL: https://oeis.org/A045558

⇱ A045558 - OEIS

login
A045558
Numbers whose factorial has '36' as its final two digits before the trailing zeros.
1
24, 63, 82, 95, 98, 104, 131, 163, 168, 172, 199, 213, 215, 234, 238, 241, 256, 284, 286, 291, 336, 343, 359, 363, 366, 408, 419, 445, 448, 504, 556, 564, 578, 617, 642, 671, 685, 693, 745, 748, 758, 769, 790
OFFSET
1,1
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)==36 \\ 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==36 \\ 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==36, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014
CROSSREFS
Sequence in context: A226883 A304547 A371174 * A352343 A022761 A090386
KEYWORD
nonn,base
AUTHOR
STATUS
approved