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A155820
Primes of the form prime(k)^2 + 2*prime(k-1) where prime(k) is the k-th prime number.
1
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
OFFSET
1,1
LINKS
EXAMPLE
prime(4)=7, prime(3)=5; 7^2+2*5=59, a prime. Hence 59 is a term.
MAPLE
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:
R; # Robert Israel, Aug 22 2023
MATHEMATICA
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 *)
CROSSREFS
Cf. A000040.
Sequence in context: A166143 A065768 A379223 * A242231 A330855 A268927
KEYWORD
nonn
AUTHOR
Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 28 2009
EXTENSIONS
More terms from Vaclav Kotesovec, Feb 14 2019
Changed offset to 1 by Vaclav Kotesovec, Feb 14 2019
STATUS
approved