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A141055
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The n-th differences of the row A141045(n,.).
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1
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-1, -2, -60, -120, -5040, -10080, -302400, -604800, -39916800, -79833600, -217945728000, -435891456000, -2615348736000, -5230697472000, -2667655710720000, -5335311421440000, -4257578514309120000, -8515157028618240000, -2810001819444019200000
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OFFSET
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0,2
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COMMENTS
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Can be thought of as the second sequence of a family: the first is A091137, the third starts 1, 2, 84, 168.
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LINKS
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FORMULA
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EXAMPLE
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The first differences of A141045(2,.) are 11-(-19)=30 and -19-11 = -30. The 2nd difference is a(2)= -30-30= -60.
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MATHEMATICA
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a[n_] := a[n] = a[n-1]*If[OddQ[n], 2, Denominator[BernoulliB[n+2]]]; a[0]=-1; Table[a[n], {n, 0, 18}] (* Jean-François Alcover, Dec 17 2014 *)
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PROG
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(PARI) a(n)=if(n, my(pr=a(n-1)); fordiv(n+2, d, if(isprime(d+1), pr*=d+1)); pr, -1) \\ Charles R Greathouse IV, Jul 08 2011
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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