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A173573
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3-Factorions: equal to the sum of the triple factorials of their digits in base 10.
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4
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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81 -> 8!!! + 1!!! = 8*5*2 + 1 = 80 + 1 = 81.
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MAPLE
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P:=proc(n, m) local a, b, i, j, k, x, w; for i from 1 by 1 to n do a:=0; b:=0; w:=0; k:=i; while k>0 do w:=k-(trunc(k/10)*10); j:=w; x:=w-m; if w=0 then b:=1; else while x>0 do j:=j*x; x:=x-m; od; b:=j; fi; a:=a+b; k:=trunc(k/10); od; if a=i then lprint(i, a); fi; od; end: P(1000, 3);
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MATHEMATICA
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stfQ[n_]:=n==Total[Times@@Range[#, 1, -3]&/@IntegerDigits[n]]; Select[Range[100], stfQ] (* Harvey P. Dale, May 31 2023 *)
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CROSSREFS
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KEYWORD
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easy,fini,full,nonn,base
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AUTHOR
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STATUS
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approved
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