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A104294
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a(n) = prime((prime(n)+1)/2).
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2
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3, 5, 7, 13, 17, 23, 29, 37, 47, 53, 67, 73, 79, 89, 103, 113, 127, 139, 151, 157, 173, 181, 197, 227, 233, 239, 251, 257, 269, 311, 317, 347, 349, 379, 383, 401, 421, 433, 449, 463, 467, 503, 509, 523, 541, 577, 613, 619, 631
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OFFSET
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2,1
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COMMENTS
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n=1 is a degenerate case because prime(1)=2, (prime(n)+1)/2 = 3/2 and there is no prime(3/2).
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LINKS
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FORMULA
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EXAMPLE
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a(5)=13 because prime((prime(5)+1)/2) = prime((11+1)/2) = prime(6) = 13;
a(7)=23 because prime((prime(7)+1)/2) = prime((17+1)/2) = prime(9) = 23.
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MATHEMATICA
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Table[Prime[(Prime[n]+1)/2], {n, 2, 50}]
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PROG
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(PARI) vector(100, n, prime((prime(n+1)+1)/2)) \\ Derek Orr, Mar 29 2015
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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