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A045525
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Numbers k such that k! has initial digit '6'.
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18
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3, 13, 18, 24, 43, 49, 72, 120, 130, 138, 174, 178, 182, 193, 203, 227, 263, 270, 290, 309, 311, 313, 315, 317, 319, 321, 355, 364, 371, 378, 390, 395, 400, 405, 418, 426, 437, 457, 460, 463, 466, 469, 491, 501, 511, 518, 525, 536, 555, 559, 563, 567, 571
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OFFSET
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1,1
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COMMENTS
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The asymptotic density of this sequence is log_10(7/6) = 0.066946... (Kunoff, 1987). - Amiram Eldar, Jul 17 2020
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LINKS
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FORMULA
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EXAMPLE
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3 is a term since 3! = 6 has the initial digit 6.
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MATHEMATICA
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Select[ Range[ 600 ], IntegerDigits[ #! ] [ [1] ] == 6 & ]
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PROG
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(PARI) isok(n) = digits(n!)[1] == 6; \\ Michel Marcus, Feb 08 2017
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CROSSREFS
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For factorials with initial digit d (1 <= d <= 9) see A045509, A045510, A045511, A045516, A045517, A045518, A282021, A045519; A045520, A045521, A045522, A045523, A045524, A045525, A045526, A045527, A045528, A045529. See also A000142, A008905.
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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