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A037168
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a(n) = 2*prime(n) - 2.
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3
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2, 4, 8, 12, 20, 24, 32, 36, 44, 56, 60, 72, 80, 84, 92, 104, 116, 120, 132, 140, 144, 156, 164, 176, 192, 200, 204, 212, 216, 224, 252, 260, 272, 276, 296, 300, 312, 324, 332, 344, 356, 360, 380, 384, 392, 396, 420, 444, 452, 456
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OFFSET
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1,1
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COMMENTS
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Original definition: Prime(n)+ Sum(prime(n-z) mod prime(n-z-1)); z=0,1...n-2 ; with offset 2.
Since prime(n+1) < 2*prime(n) for all n, the "mod" in the sum is equivalent to "-", making it telescopic and equal to prime(n)-2. - M. F. Hasler, Jun 29 2013
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LINKS
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FORMULA
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a(n) = 2 * prime(n) - 2 = 2 * phi(prime(n)). - Alonso del Arte, Jun 30 2013
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EXAMPLE
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a(3) = 8 since the third prime is 5 and 2 * 5 - 2 = 8.
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Armand Turpel (armandt(AT)unforgettable.com)
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EXTENSIONS
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STATUS
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approved
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