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A092474
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a(n) is the first term in a sequence of primes such that a(n)+4m^2 is also prime for m = 1 to n.
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1
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3, 3, 7, 7, 7, 7, 37, 37, 163, 163, 163, 163, 163, 163, 163, 163, 163, 163, 163
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| a(1) starts sequence A023200; a(2) starts sequence A049492. (I've searched up to 2000000 but haven't yet found the terms from a(20) onward.)
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EXAMPLE
| a(5) = 7.
7+4(1^2) = 7+4(1) = 7+4 = 11 which is prime.
7+4(2^2) = 7+4(4) = 7+16 = 23 which is prime.
7+4(3^2) = 7+4(9) = 7+36 = 43 which is prime.
7+4(4^2) = 7+4(16) = 7+64 = 71 which is prime.
7+4(5^2) = 7+4(25) = 7+100 = 107 which is prime.
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CROSSREFS
| Sequence in context: A160515 A105670 A003817 * A107470 A071042 A128053
Adjacent sequences: A092471 A092472 A092473 * A092475 A092476 A092477
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KEYWORD
| nonn
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AUTHOR
| Ray G. Opao (qzxpqbp(AT)gmail.com), Mar 25 2004
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