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A303091 Primes of the form 5^k + 2*k. 0

%I

%S 7,29,131,78139,3814697265661,7450580596923828179,

%T 4336808689942017736029811203479766845703247

%N Primes of the form 5^k + 2*k.

%C a(8) has 504 digits and is too large to be included.

%e 7 is a member of the sequence because 7 is a prime and 5^1 + 2*1 = 7.

%e 29 is a member of the sequence because 29 is a prime and 5^2 + 2*2 = 29.

%e 131 is a member of the sequence because 131 is a prime and 5^3 + 2*3 = 131.

%p a:=k->`if`(isprime(5^k+2*k),5^k+2*k,NULL): seq(a(k),k=1..1500);

%t Select[Table[5^k+2k,{k,80}],PrimeQ] (* _Harvey P. Dale_, Jul 11 2021 *)

%o (GAP) Filtered(List([1..700],k ->5^k+2*k),IsPrime);

%Y Cf. A299642, A299643, A297663, A303090.

%K nonn

%O 1,1

%A _Muniru A Asiru_, Apr 18 2018

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Last modified January 22 18:37 EST 2022. Contains 350488 sequences. (Running on oeis4.)