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A072208
a(n)-th factorial is the smallest factorial containing exactly n 8's, or 0 if no such number exists.
8
11, 9, 36, 16, 30, 27, 39, 33, 44, 58, 56, 64, 80, 70, 72, 94, 97, 71, 108, 143, 120, 134, 118, 162, 125, 133, 151, 137, 138, 159, 169, 197, 184, 171, 178, 176, 206, 177, 191, 208, 207, 240, 252, 232, 239, 270, 229, 308, 243, 223, 278, 257, 250, 0, 303, 242, 311
OFFSET
1,1
COMMENTS
It is conjectured that a(54)=0 since no factorial < 10000 contained just 54 eights.
EXAMPLE
a(2)=9 since 9th factorial i.e. 9!=362880 contains exactly two 8's.
MATHEMATICA
Do[k = 1; While[ Count[IntegerDigits[k! ], 8] != n, k++ ]; Print[k], {n, 1, 60}]
Transpose[Flatten[Table[Select[Table[{n, DigitCount[n!, 10, 8]}, {n, 500}], Last[#] == i&, 1], {i, 50}], 1]][[1]] (* Harvey P. Dale, Sep 13 2013 *)
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Jul 30 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jul 31 2002
STATUS
approved