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Search: id:A086408
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| A086408 |
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a[1]=1; a[n+1]=a[n]-1 if mod[prime[a[n]],6]=1, else a[n+1]=a[n]+4. |
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+0
3
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| 1, 5, 9, 13, 17, 21, 20, 24, 28, 32, 36, 35, 39, 43, 47, 46, 45, 49, 53, 52, 56, 60, 64, 68, 67, 66, 70, 69, 73, 72, 76, 80, 79, 83, 87, 91, 95, 94, 98, 102, 106, 105, 104, 108, 112, 111, 110, 109, 113, 117, 116, 120, 124, 128, 132, 136, 135, 139, 143, 142, 146, 150
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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There is a cycle starting with a(117)=270: ...270,274,273,272,271,270,...
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EXAMPLE
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a(3)=9 because a(2)=5, prime[5]=11=!=1 (mod 6) and a(3)=a(2)+4
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MATHEMATICA
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b=1; Prepend[Table[b+=If[Mod[Prime[b], 6]==1, -1, 4], {i, 152}], 1]
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CROSSREFS
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Cf. A086407, A086409.
Sequence in context: A116616 A080590 A051541 this_sequence A141135 A162502 A016813
Adjacent sequences: A086405 A086406 A086407 this_sequence A086409 A086410 A086411
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KEYWORD
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easy,nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Jul 18 2003
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