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A110728
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Digital factorial: a(0) = 1, a(n) = n * (the sum of the digits of a(n-1)).
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4
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1, 1, 2, 6, 24, 30, 18, 63, 72, 81, 90, 99, 216, 117, 126, 135, 144, 153, 162, 171, 180, 189, 396, 414, 216, 225, 234, 243, 252, 261, 270, 279, 576, 594, 612, 315, 324, 333, 342, 351, 360, 369, 756, 774, 792, 810, 414, 423, 432, 441, 450, 459, 936, 954, 972
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OFFSET
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0,3
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LINKS
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EXAMPLE
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a(4) = 24, a(5) = 5*(2+4) = 30, a(6) = 6*3 = 18.
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MAPLE
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a:= proc(n) option remember; `if`(n=0, 1,
n*add(i, i=convert(a(n-1), base, 10)))
end:
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MATHEMATICA
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PROG
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(PARI) s=vector(1001, n, 1); for(n=2, #s, s[n]=(n-1)*sumdigits(s[n-1])); s \\ Colin Barker, Nov 20 2014
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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a(22) and a(32) corrected, name clarified, and more terms added by Colin Barker, Nov 20 2014
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STATUS
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approved
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