# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a087691 Showing 1-1 of 1 %I A087691 #18 Dec 02 2022 07:05:10 %S A087691 9,49,121,361,529,961,1849,2209,3481,4489,5041,6241,6889,10609,11449, %T A087691 16129,17161,19321,22801,26569,27889,32041,36481,39601,44521,49729, %U A087691 51529,57121,63001,69169,73441,80089,94249,96721,109561,120409,128881 %N A087691 Squares of primes of the form 4*k+3. %H A087691 Harvey P. Dale, Table of n, a(n) for n = 1..10000 %F A087691 a(n) = A002145(n)^2. %F A087691 a(n) ~ 4n^2 * (log n)^2. - _Charles R Greathouse IV_, Sep 20 2016 %F A087691 From _Amiram Eldar_, Dec 02 2022: (Start) %F A087691 Product_{n>=1} (1 + 1/a(n)) = A243381. %F A087691 Product_{n>=1} (1 - 1/a(n)) = A243379. (End) %t A087691 Select[4*Range[0,100]+3,PrimeQ]^2 (* _Harvey P. Dale_, Sep 10 2012 *) %o A087691 (PARI) p4np3(n)= forprime(x=3,n,if(x%4==3,y=x*x; print1(y, ", "))); %Y A087691 Cf. A002145, A243379, A243381. %K A087691 nonn,easy %O A087691 1,1 %A A087691 _Cino Hilliard_, Sep 27 2003 %E A087691 More terms from _Ray Chandler_, Oct 26 2003 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE