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A109738
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a(0)=1; for n>0, a(n) = a(n-1) S prime(n), where S is + if n is odd and a(n-1) is even, x if n is odd and a(n-1) is odd, - if n is even and a(n-1) is even, + if n is even and a(n-1) is odd.
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1
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1, 2, -1, -5, 2, 13, 26, 43, 62, 85, 114, 145, 182, 223, 266, 313, 366, 425, 486, 553, 624, 697, 776, 859, 948, 1045, 1146, 1249, 1356, 1465, 1578, 1705, 1836, 1973, 2112, 2261, 2412, 2569, 2732, 2899, 3072, 3251, 3432, 3623, 3816, 4013, 4212, 4423, 4646, 4873
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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MATHEMATICA
| f[l_] := Append[l, Apply[{Subtract, Plus, Plus, Times}[[2*Mod[Length[l], 2] + Mod[Last[l], 2] + 1]], {Last[l], Prime[Length[l]]}]]; Nest[f, {1}, 50] (*Chandler*)
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CROSSREFS
| A corrected version of A109623.
Sequence in context: A087123 A097131 A192263 * A143891 A030400 A115345
Adjacent sequences: A109735 A109736 A109737 * A109739 A109740 A109741
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KEYWORD
| sign
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), following a communication from Harry Yang (yexing_yang(AT)msn.com), Aug 11 2005
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. Wilson v, Aug 12 2005
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