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A047906
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a(n+1) = a(n) - n (if n is odd), a(n+1) = a(n) * n (if n is even).
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2
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1, 0, 0, -3, -12, -17, -102, -109, -872, -881, -8810, -8821, -105852, -105865, -1482110, -1482125, -23714000, -23714017, -426852306, -426852325, -8537046500, -8537046521, -187815023462, -187815023485, -4507560563640
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OFFSET
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1,4
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LINKS
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MATHEMATICA
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Transpose[NestList[{First[#]+1, If[OddQ[First[#]], Last[#]-First[#], Last[#]*First[#]]}&, {1, 1}, 30]][[2]] (* Harvey P. Dale, Dec 12 2011 *)
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PROG
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(Haskell)
a047906 n = a047906_list !! (n-1)
a047906_list = 1 : zipWith uncurry
(cycle [(-), (*)]) (zip a047906_list [1..])
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CROSSREFS
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KEYWORD
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sign,easy,nice
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AUTHOR
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Miklos SZABO (mike(AT)ludens.elte.hu)
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STATUS
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approved
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