A225874 - OEIS

A225874

Primes of the form 5*p^2+5*p+1, where p is a prime.

%I #8 Sep 08 2022 08:46:05

%S 31,61,151,281,661,911,1531,1901,9461,18911,25561,27011,31601,51511,

%T 57781,59951,81281,86461,94531,97301,111751,114761,140281,183361,

%U 187211,286801,347161,363151,401861,485161,603781,697511,720101,758551,806011,939611,965801

%N Primes of the form 5*p^2+5*p+1, where p is a prime.

%C Primes generated in A175063.

%C The square roots of (4*a(n)+1)/5 are in A072055. [_Bruno Berselli_, May 19 2013]

%t Select[Table[p=Prime[n]; 5*p^2+5*p+1, {n,85}], PrimeQ]

%o (Magma) [a: p in PrimesUpTo(500) | IsPrime(a) where a is 5*p^2+5*p+1]; // _Bruno Berselli_, May 19 2013

%Y Cf. A175063.

%K nonn

%O 1,1

%A _Jayanta Basu_, May 19 2013