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Search: id:A079141
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| A079141 |
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Primes of the form p^2 + 6 where p is prime. |
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+0
2
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| 31, 127, 367, 967, 3727, 6247, 7927, 11887, 17167, 22807, 39607, 72367, 109567, 160807, 185767, 323767, 502687, 737887, 863047, 885487, 942847, 982087, 1079527, 1560007, 1739767, 1852327, 1985287, 2105407, 2343967, 2399407
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sum of reciprocals = 0.044715...
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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MATHEMATICA
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f[n_]:=n^2+6; lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, f[p]]], {n, 7!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jul 17 2009]
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PROGRAM
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(PARI) sqppn(n) = {sr=0; forprime(x=3, n, y = x*x+6; if(isprime(y), print1(y" "); sr+=1.0/y; ); ); print(); print(sr); } \\ Primes of the form p^2 + 6 and the sum of the reciprocals.
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CROSSREFS
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Cf. A056909.
Sequence in context: A095322 A127578 A158563 this_sequence A049203 A065403 A035502
Adjacent sequences: A079138 A079139 A079140 this_sequence A079142 A079143 A079144
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Dec 26 2002
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