%I #18 Dec 02 2022 07:05:10

%S 9,49,121,361,529,961,1849,2209,3481,4489,5041,6241,6889,10609,11449,

%T 16129,17161,19321,22801,26569,27889,32041,36481,39601,44521,49729,

%U 51529,57121,63001,69169,73441,80089,94249,96721,109561,120409,128881

%N Squares of primes of the form 4*k+3.

%H Harvey P. Dale, <a href="/A087691/b087691.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A002145(n)^2.

%F a(n) ~ 4n^2 * (log n)^2. - _Charles R Greathouse IV_, Sep 20 2016

%F From _Amiram Eldar_, Dec 02 2022: (Start)

%F Product_{n>=1} (1 + 1/a(n)) = A243381.

%F Product_{n>=1} (1 - 1/a(n)) = A243379. (End)

%t Select[4*Range[0,100]+3,PrimeQ]^2 (* _Harvey P. Dale_, Sep 10 2012 *)

%o (PARI) p4np3(n)= forprime(x=3,n,if(x%4==3,y=x*x; print1(y, ", ")));

%Y Cf. A002145, A243379, A243381.

%K nonn,easy

%O 1,1

%A _Cino Hilliard_, Sep 27 2003

%E More terms from _Ray Chandler_, Oct 26 2003