A073476 - OEIS

%I #8 Nov 30 2024 14:56:47

%S 2,2222,2732,3998,5356,5358,5626,8034,9402,9972,10006,10930,12188,

%T 12322,12702,13372,14536,15038,15962,21396,24704,25446,27118,29566,

%U 36126,36604,36732,36734,37550,37552,37554,44176,44218,48164,48978

%N Numbers k such that k^4 + 1, (k+2)^4 + 1 and (k+4)^4 + 1 are all primes.

%H Robert Israel, <a href="/A073476/b073476.txt">Table of n, a(n) for n = 1..1000</a>

%e 2222^4+1, 2224^4+1 and 2226^4+1 are prime

%p N:= 10^5: # to get all terms <= N

%p R:= select(t -> isprime(t^4+1), [seq(i,i=2..N,2)]):

%p V:= select(i -> R[i+2]=R[i]+4, [$1..nops(R)-2]):

%p R[V]; # _Robert Israel_, Apr 20 2017

%t Select[Range[5000], PrimeQ[ #^4 + 1] && PrimeQ[(# + 2)^4 + 1] && PrimeQ[(# + 4)^4 + 1] & ]

%Y Cf. A000068, n such that n^4+1 is prime.

%K nonn

%O 1,1

%A _Martin Raab_, Aug 26 2002

%E More terms from _Robert G. Wilson v_, Aug 28 2002