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 A047906 a(n+1) = a(n) - n (if n is odd), a(n+1) = a(n) * n (if n is even). 2
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..500 MAPLE P:=proc(q) local a, b, n; a:=1; b:=[1]; for n from 1 to q do a:=(1-(-1)^n)/2*(a-n)+(1+(-1)^n)/2*(a*n); b:=[op(b), a]; od; op(b); end: P(24); # Paolo P. Lava, Oct 12 2018 MATHEMATICA Transpose[NestList[{First[#]+1, If[OddQ[First[#]], Last[#]-First[#], Last[#]*First[#]]}&, {1, 1}, 30]][[2]] (* Harvey P. Dale, Dec 12 2011 *) PROG (Haskell) a047906 n = a047906_list !! (n-1) a047906_list = 1 : zipWith uncurry                            (cycle [(-), (*)]) (zip a047906_list [1..]) -- Reinhard Zumkeller, Nov 14 2013 CROSSREFS Cf. A000124, A000142, A047907. Sequence in context: A082965 A045549 A103249 * A104641 A032703 A234904 Adjacent sequences:  A047903 A047904 A047905 * A047907 A047908 A047909 KEYWORD sign,easy,nice AUTHOR Miklos SZABO (mike(AT)ludens.elte.hu) STATUS approved

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Last modified August 5 07:21 EDT 2020. Contains 336209 sequences. (Running on oeis4.)