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%I #15 Feb 19 2024 01:55:12
%S 1,0,0,-3,-12,-17,-102,-109,-872,-881,-8810,-8821,-105852,-105865,
%T -1482110,-1482125,-23714000,-23714017,-426852306,-426852325,
%U -8537046500,-8537046521,-187815023462,-187815023485,-4507560563640
%N a(n+1) = a(n) - n (if n is odd), a(n+1) = a(n) * n (if n is even).
%H Reinhard Zumkeller, <a href="/A047906/b047906.txt">Table of n, a(n) for n = 1..500</a>
%t Transpose[NestList[{First[#]+1,If[OddQ[First[#]],Last[#]-First[#], Last[#]*First[#]]}&,{1,1},30]][[2]] (* _Harvey P. Dale_, Dec 12 2011 *)
%o (Haskell)
%o a047906 n = a047906_list !! (n-1)
%o a047906_list = 1 : zipWith uncurry
%o (cycle [(-), (*)]) (zip a047906_list [1..])
%o -- _Reinhard Zumkeller_, Nov 14 2013
%Y Cf. A000124, A000142, A047907.
%K sign,easy,nice
%O 1,4
%A Miklos SZABO (mike(AT)ludens.elte.hu)
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