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A173574 4-Factorions: equal to the sum of the quadruple factorials of their digits in base 10. 2
1, 2, 3, 4, 5, 49 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

49 -> 4!!!! + 9!!!! = 4 + 9*5 = 4 +45 = 49.

MAPLE

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, 4);

MATHEMATICA

qfd[n_]:=Times@@Range[n, 1, -4]; Select[Range[50], Total[qfd/@ IntegerDigits[ #]] == #&] (* Harvey P. Dale, Dec 15 2018 *)

CROSSREFS

Cf. A007662, A014080, A097653, A173573, A173575-A173577

Sequence in context: A028427 A037329 A344848 * A278940 A273470 A303163

Adjacent sequences:  A173571 A173572 A173573 * A173575 A173576 A173577

KEYWORD

easy,fini,nonn,base

AUTHOR

Paolo P. Lava, Feb 22 2010

STATUS

approved

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Last modified November 30 06:28 EST 2021. Contains 349419 sequences. (Running on oeis4.)