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A155820
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Primes of the form prime(k)^2 + 2*prime(k-1) where prime(k) is the k-th prime number.
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1
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13, 31, 59, 191, 887, 1019, 1931, 2903, 5471, 8087, 9587, 19031, 23099, 33119, 57587, 80651, 129587, 168083, 188351, 327179, 359987, 414731, 678971, 846383, 898691, 910103, 984047, 1040387, 1044479, 1132091, 1331711, 1411331, 1444787, 1517819, 1669259, 1909907
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OFFSET
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1,1
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LINKS
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EXAMPLE
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prime(4)=7, prime(3)=5; 7^2+2*5=59, a prime. Hence 59 is a term.
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MAPLE
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count:= 0: q:= 2: R:= NULL:
while count < 100 do
p:= q; q:= nextprime(q);
v:= q^2 + 2*p;
if isprime(v) then count:= count+1; R:= R, v; fi;
od:
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MATHEMATICA
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list = {}; Do[m = Prime[k]^2 + 2*Prime[k - 1]; If[PrimeQ[m], AppendTo[list, m]], {k, 2, 300}]; list (* Vaclav Kotesovec, Feb 14 2019 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 28 2009
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EXTENSIONS
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STATUS
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approved
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