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Search: id:A105366
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| A105366 |
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Rearrangement of positive integers according to parity of (prime(n)-1)/2 (see comments). |
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+0
2
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| 1, 2, 4, 3, 5, 6, 8, 7, 11, 9, 13, 10, 12, 17, 19, 14, 23, 15, 29, 31, 16, 37, 41, 18, 20, 21, 43, 47, 22, 24, 53, 59, 25, 61, 26, 67, 27, 71, 73, 28, 79, 30, 83, 32, 33, 89, 97, 101, 103, 34, 35, 107, 36, 109, 38, 113, 39, 127, 40, 42
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(1)=1, for n>1: if (prime(n)-1)/2 is odd/even then a(n) is the next prime/composite number.
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MATHEMATICA
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p=Prime[Range[100]]; s=Complement[Range[100], p]; bb={1}; is=1; ip=0; Do[If[EvenQ[(Prime[i]-1)/2], is=is+1; bb=Append[bb, s[[is]]], ip=ip+1; bb=Append[bb, p[[ip]]]], {i, 2, 60}]; bb
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CROSSREFS
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Cf. A105365.
Sequence in context: A075618 A095689 A083194 this_sequence A077156 A132948 A102569
Adjacent sequences: A105363 A105364 A105365 this_sequence A105367 A105368 A105369
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Apr 01 2005
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