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A045560 Numbers n such that final 2 nonzero digits of n! are '48'. 1
30, 77, 81, 142, 154, 157, 190, 245, 248, 267, 311, 332, 345, 348, 370, 373, 395, 398, 403, 427, 433, 444, 475, 476, 508, 519, 553, 562, 567, 584, 591, 618, 643, 658, 669, 682, 696, 727, 730, 750, 751, 796, 811 (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)==48 \\ 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==48 \\ 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==48, listput(v, n); if(#v==100, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 22 2014

CROSSREFS

Sequence in context: A179321 A039517 A185479 * A159219 A098998 A044168

Adjacent sequences:  A045557 A045558 A045559 * A045561 A045562 A045563

KEYWORD

nonn,base

AUTHOR

Jeff Burch

STATUS

approved

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Last modified February 16 15:17 EST 2020. Contains 331961 sequences. (Running on oeis4.)