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Search: id:A065856
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| A065856 |
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The (2^n)-th composite number. |
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+0
4
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| 4, 6, 9, 15, 26, 48, 88, 168, 323, 627, 1225, 2406, 4736, 9351, 18504, 36655, 72730, 144450, 287147, 571208, 1136971, 2264215, 4510963, 8990492, 17923944, 35743996, 71298762, 142249762, 283859985, 566537515, 1130886504, 2257704401
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n)-PrimePi[a(n)]-1=2^n.
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EXAMPLE
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composite[1] = composite[2^0] = 4, composite[2] = composite[2^1] = 6, composite[1024] = composite[2^10] = 1225, composite[1073741824}] = composite[2^30] = 1130886504.
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MATHEMATICA
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Composite[n_Integer] := Block[ {k = n + PrimePi[n] + 1 }, While[ k != n + PrimePi[k] + 1, k = n + PrimePi[k] + 1]; Return[ k ]]; Table[ Composite[2^n], {n, 0, 36} ]
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CROSSREFS
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Cf. A033844, A002808, A018252, A062298, A000720, A065855
Sequence in context: A087718 A033476 A118696 this_sequence A136357 A136356 A136358
Adjacent sequences: A065853 A065854 A065855 this_sequence A065857 A065858 A065859
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Nov 26 2001
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 26 2001
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