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%I #15 Sep 08 2022 08:45:45
%S 1,1,1,3,4,5,18,28,40,162,280,440,1944,3640,6160,29160,58240,104720,
%T 524880,1106560,2094400,11022480,24344320,48171200,264539520,
%U 608608000,1252451200,7142567040,17041024000,36321084800,214277011200,528271744000,1162274713600
%N Triple factorials n!!!: a(n) = n*a(n-3).
%C This definition of triple factorials starts with a(1)=a(2)=1. The main version is A007661.
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Factorial#Multifactorials">Multifactorials</a>
%p A161474 := proc(n) if n < 3 then 1 ; else procname(n-3)*n ; fi; end: seq(A161474(n),n=0..80) ; # _R. J. Mathar_, Jun 16 2009
%t multiFactorialRev[n_, k_] := If[n < k, 1, If[n >= k, n*multiFactorialRev[n - k, k]]]; Array[ multiFactorialRev[#, 3] &, 32] (* _Robert G. Wilson v_, Aug 29 2012 *)
%o (Magma) TripleFactorial:=func<n | &*[n..3 by -3]>; [TripleFactorial(n): n in [1..35]]; // _Vincenzo Librandi_, Apr 08 2016
%Y Cf. A002110, A006882, A001813.
%K nonn
%O 0,4
%A Asbel Torres da Cunha (asbeltc(AT)gmail.com), Jun 11 2009
%E Corrected and extended by _R. J. Mathar_, Jun 16 2009
%E a(0)=1 prepended by _Alois P. Heinz_, May 06 2020
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