A110873 - OEIS

%I #11 Oct 12 2019 11:57:40

%S 9,49,81,225,289,529,625,1089,1521,1681,2209,3025,5041,6561,7569,7921,

%T 9025,10609,12769,14641,16129,16641,18769,20449,22801,23409,28561,

%U 31329,36481,37249,39601,40401,46225,49729,50625,69169,70225,73441,78961

%N Squares of the form 8p - 7, where p is prime.

%H G. C. Greubel, <a href="/A110873/b110873.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = A110872(n)^2 = 8*A055469(n) - 7.

%F a(n) = 8*A055469(n)-7.

%t Select[Table[n^2, {n, 300}], PrimeQ[(# + 7)/8] &] (* _Ray Chandler_, Oct 01 2005 *)

%t Select[8#-7&/@Prime[Range[1300]],IntegerQ[Sqrt[#]]&] (* _Harvey P. Dale_, Apr 11 2018 *)

%o (PARI) for(i=1,1000,n=i^2+7;if(n%8==0&&isprime(n/8),print1(n-7,","))) (Klasen)

%Y Cf. A055469, A067186, A110872.

%K nonn

%O 1,1

%A _Giovanni Teofilatto_, Sep 18 2005

%E Extended by Lambert Klasen (lambert.klasen(AT)gmx.net) and _Ray Chandler_, Oct 01 2005