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Search: id:A109738
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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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+0
2
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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; listen)
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OFFSET
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0,2
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MATHEMATICA
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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
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A corrected version of A109623.
Adjacent sequences: A109735 A109736 A109737 this_sequence A109739 A109740 A109741
Sequence in context: A109191 A087123 A097131 this_sequence A143891 A030400 A115345
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KEYWORD
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sign
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AUTHOR
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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
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. Wilson v, Aug 12 2005
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