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A045567 Numbers n such that final 2 nonzero digits of n! are '84'. 1
25, 26, 42, 55, 103, 136, 140, 147, 158, 169, 231, 261, 265, 272, 281, 333, 344, 356, 380, 389, 410, 460, 472, 486, 503, 565, 582, 595, 598, 629, 662, 674, 677, 683, 694, 700, 701, 712, 742, 763, 777, 789, 839 (list; graph; refs; listen; history; text; internal format)
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)==84 \\ 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==84 \\ 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==84, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A111168 A195331 A175426 * A141278 A022395 A042260

Adjacent sequences:  A045564 A045565 A045566 * A045568 A045569 A045570

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved

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Last modified November 19 16:06 EST 2019. Contains 329320 sequences. (Running on oeis4.)