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%I #38 Feb 17 2024 10:29:12
%S 1,2,4,20,21,26,30,33,37,39,42,44,45,48,51,52,53,56,59,60,64,65,67,68,
%T 69,72,75,78,79,80,81,82,83,84,88,91,93,94,95,96,97,98,99,116,124,134,
%U 136,140,141,149,164,165,166,170,174,180,186,188,196,198,200,202,205
%N Numbers k such that k! contains k as a string of digits.
%H T. D. Noe, <a href="/A033180/b033180.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>
%F A067109(a(n)) > 0. [_Reinhard Zumkeller_, Aug 23 2008]
%t Select[Range[210],MemberQ[Partition[IntegerDigits[#!],IntegerLength[#], 1], IntegerDigits[ #]]&] (* _Harvey P. Dale_, Dec 25 2011 *)
%t Select[Range@500, StringContainsQ[ToString[#!], ToString[#]] &] (* _Ivan N. Ianakiev_, Jul 28 2016 *)
%t Select[Range[210],SequenceCount[IntegerDigits[#!],IntegerDigits[#]]>0&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Aug 14 2017 *)
%o (Haskell)
%o a033180 n = a033180_list !! (n-1)
%o a033180_list = filter ((> 0) . a067109) [1..]
%o -- _Reinhard Zumkeller_, Aug 28 2014
%o (Python)
%o from math import factorial
%o def ok(n): return str(n) in str(factorial(n))
%o print(list(filter(ok, range(206)))) # _Michael S. Branicky_, Aug 07 2021
%Y Cf. A000142.
%K nonn,base,easy,nice
%O 1,2
%A _Jeff Burch_
%E More terms from _David W. Wilson_
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