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A045555 Numbers n such that final 2 nonzero digits of n! are '24'. 1
4, 37, 49, 52, 58, 69, 75, 76, 87, 117, 179, 205, 277, 289, 307, 321, 339, 383, 394, 409, 411, 416, 425, 426, 461, 468, 493, 512, 546, 563, 621, 645, 648, 717, 724, 725, 726, 759, 760, 766, 780, 807, 821, 827, 831 (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)==24 \\ 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==24 \\ 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==24, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A222517 A103369 A031189 * A297803 A183378 A145401

Adjacent sequences:  A045552 A045553 A045554 * A045556 A045557 A045558

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved

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Last modified November 15 19:18 EST 2019. Contains 329149 sequences. (Running on oeis4.)