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%I #8 Jul 03 2017 16:13:11
%S 1,1,2,-6,-4,-25,-24,-42,336,216,2500,2376,4032,-52416,-33264,-562500,
%T -532224,-891072,16039296,10112256,225000000,212357376,352864512,
%U -8115883776,-5096577024,-140625000000,-132511002624,-219128861952,6135608134656,3842819076096,126562500000000
%N Row 5 of array in A288580.
%D F. Smarandache, Back and Forth Factorials, Arizona State Univ., Special Collections, 1972.
%H J. Dezert, ed., <a href="http://www.mathematicsmagazine.com/corresp/J_Dezert/JDezert.htm">Smarandacheials (1)</a>, Mathematics Magazine for Grades 1-12, No. 4, 2004.
%H J. Dezert, ed., <a href="http://www.mathematicsmagazine.com/corresp/J_Dezert/JDezert2.htm">Smarandacheials (2)</a>, Mathematics Magazine for Grades 1-12, No. 4, 2004.
%F a(n) = !n!_5 = Prod_{i=0, 1, 2, ... .}_{0<|n-5i|<=n}(n-5i) = n(n-5)(n-10)....
%e !11!_5 = 11(11-5)(11-10)(11-15)(11-20) = 11(6)(1)(-4)(-9) = 2376.
%p T:=proc(n,k) local i,p;
%p p:=1;
%p for i from 0 to floor(2*n/k) do
%p if n-k*i <> 0 then p:=p*(n-k*i) fi; od:
%p p;
%p end;
%p r:=k->[seq(T(n,k), n=0..60)]; r(5); # _N. J. A. Sloane_, Jul 03 2017
%Y Cf. A288580.
%K sign
%O 0,3
%A J. Dezert (Jean.Dezert(AT)onera.fr), Mar 21 2004
%E Entry revised by _N. J. A. Sloane_, Jul 03 2017
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