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URL: https://oeis.org/A045559

⇱ A045559 - OEIS

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A045559
Numbers whose factorial has '44' as its final two digits before the trailing zeros.
1
21, 78, 112, 134, 135, 141, 155, 182, 196, 202, 206, 259, 260, 266, 320, 323, 330, 413, 418, 422, 428, 437, 442, 463, 465, 485, 490, 517, 545, 548, 559, 566, 572, 579, 620, 623, 650, 651, 667, 680, 728, 768, 781, 820, 823, 833, 844
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)==44 \\ 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==44 \\ 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==44, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014
CROSSREFS
Sequence in context: A085027 A143206 A182754 * A144314 A010009 A172082
KEYWORD
nonn,base
AUTHOR
STATUS
approved