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Search: id:A106349
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| A106349 |
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Primes indexed by semiprimes. |
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+0
14
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| 7, 13, 23, 29, 43, 47, 73, 79, 97, 101, 137, 139, 149, 163, 167, 199, 227, 233, 257, 269, 271, 293, 313, 347, 373, 389, 421, 439, 443, 449, 467, 487, 491, 499, 577, 607, 631, 647, 653, 661, 673, 677, 727, 751, 757, 811, 821, 823, 829, 839, 907, 929, 937, 947
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This is the sequence of the n-th prime for n = {4,6,9,10,14,15,21,22,25,26,33,34,35,38,39,46,49,51,...}. Not to be confused with A106350: semiprimes indexed by primes.
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FORMULA
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a(n) = prime(semiprime(n)). a(n) = A000040(A001358(n)). pi(a(n)) = p*q for some primes p and q.
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EXAMPLE
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a(1) = 7 because semiprime(1) = 4, so prime(semiprime(1)) = prime(4) = 7.
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CROSSREFS
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Cf. A000040, A001358, A007097, A091022, A105997, A105998, A106350.
Sequence in context: A034112 A163676 A043104 this_sequence A048449 A147812 A043884
Adjacent sequences: A106346 A106347 A106348 this_sequence A106350 A106351 A106352
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 29 2005
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