A302087 Numbers k such that k^2+1 and (k+6)^2+1 are both prime.
4, 10, 14, 20, 84, 110, 120, 124, 150, 170, 204, 224, 230, 250, 264, 300, 400, 430, 464, 490, 570, 674, 680, 690, 930, 960, 1004, 1054, 1060, 1140, 1144, 1150, 1314, 1410, 1434, 1550, 1564, 1570, 1580, 1654, 1784, 1870, 1964, 1974, 2050, 2074, 2080, 2120, 2260, 2304, 2314
Offset: 1
Keywords
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000
Programs
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Magma
[n: n in [1..2500] | IsPrime(n^2+1) and IsPrime((n+6)^2+1)]; // Vincenzo Librandi, Apr 02 2018
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Maple
select(k->isprime(k^2+1) and isprime((k+6)^2+1),[$1..3000]); # Muniru A Asiru, Apr 02 2018
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Mathematica
Select[Range[3000], PrimeQ[#^2 + 1] && PrimeQ[(# + 6)^2 + 1]&] (* Vincenzo Librandi, Apr 02 2018 *)
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PARI
isok(k) = isprime(k^2+1) && isprime((k+6)^2+1); \\ Altug Alkan, Apr 02 2018
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Python
from sympy import isprime k, klist, A302087_list = 0, [isprime(i**2+1) for i in range(6)], [] while len(A302087_list) < 10000: i = isprime((k+6)**2+1) if klist[0] and i: A302087_list.append(k) k += 1 klist = klist[1:] + [i] # Chai Wah Wu, Apr 01 2018