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A302087 Numbers k such that k^2+1 and (k+6)^2+1 are both prime. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

MAPLE

select(k->isprime(k^2+1) and isprime((k+6)^2+1), [$1..3000]); # Muniru A Asiru, Apr 02 2018

MATHEMATICA

Select[Range[3000], PrimeQ[#^2 + 1] && PrimeQ[(# + 6)^2 + 1]&] (* Vincenzo Librandi, Apr 02 2018 *)

PROG

(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

(MAGMA) [n: n in [1..2500] | IsPrime(n^2+1) and IsPrime((n+6)^2+1)]; // Vincenzo Librandi, Apr 02 2018

(PARI) isok(k) = isprime(k^2+1) && isprime((k+6)^2+1); \\ Altug Alkan, Apr 02 2018

CROSSREFS

Cf. A005574, A023201, A096012, A302021.

Sequence in context: A310422 A310423 A114335 * A329103 A099355 A161366

Adjacent sequences:  A302084 A302085 A302086 * A302088 A302089 A302090

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Mar 31 2018

STATUS

approved

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Last modified October 21 08:49 EDT 2020. Contains 337911 sequences. (Running on oeis4.)