A033147 - OEIS

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A033147

Numbers k such that the decimal expansion of k! begins with k.

1, 2, 198, 217, 5936, 7400, 8999, 11672, 5814279, 9242361, 10430012, 21603226, 28563733, 252544448, 5042264464, 5795685640, 421559495895

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OFFSET

1,2

COMMENTS

The inclusion of the deleted term k=171489648 seems likely to have resulted from a precision problem: computing as an intermediate result x = log_10(k!) = 1337609557.23423787495... and storing that result rounded to its nearest IEEE 754 double-precision binary floating-point number D = 5610341116345793 / 2^22 would result in floor(10^(D-1337609549)) = 171489648 = k, whereas floor(10^(x-1337609549)) = 171489634. - Jon E. Schoenfield, Nov 07 2014

LINKS

Table of n, a(n) for n=1..17.

Index entries for sequences related to factorial numbers

EXAMPLE

From Jon E. Schoenfield, Nov 07 2014: (Start)

198! = 198.155...*10^368

217! = 217.443...*10^412

5936! = 5936.670...*10^19820

7400! = 7400.662...*10^25417

8999! = 8999.544...*10^31674

11672! = 11672.612...*10^42401

5814279! = 5814279.634...*10^36805554