This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A092397 #9 Jul 03 2017 16:12:29
%S A092397 1,1,-2,-9,-8,40,324,280,-2240,-26244,-22400,246400,3779136,3203200,
%T A092397 -44844800,-850305600,-717516800,12197785600,275499014400,
%U A092397 231757926400,-4635158528000,-121495065350400,-101973487616000,2345390215168000,69981157641830400,58634755379200000
%N A092397 Row 3 of array in A288580.
%D A092397 F. Smarandache, Back and Forth Factorials, Arizona State Univ., Special Collections, 1972.
%H A092397 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 A092397 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 A092397 a(n) = !n!_3 = Prod_{i=0, 1, 2, ... .}_{0<|n-3i|<=n}(n-3i) = n(n-3)(n-6)...
%e A092397 !7!_3 = 7(7-3)(7-6)(7-9)(7-12) = 7(4)(1)(-2)(-5) = 280.
%p A092397 T:=proc(n,k) local i,p;
%p A092397 p:=1;
%p A092397 for i from 0 to floor(2*n/k) do
%p A092397 if n-k*i <> 0 then p:=p*(n-k*i) fi; od:
%p A092397 p;
%p A092397 end;
%p A092397 r:=k->[seq(T(n,k), n=0..60)]; r(3); # _N. J. A. Sloane_, Jul 03 2017
%Y A092397 Cf. A288580.
%K A092397 sign
%O A092397 0,3
%A A092397 J. Dezert (Jean.Dezert(AT)onera.fr), Mar 21 2004
%E A092397 Entry revised by _N. J. A. Sloane_, Jul 03 2017