This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A088503 #24 Sep 08 2022 08:45:11 %S A088503 3,5,7,11,13,17,25,29,31,35,41,43,49,55,67,77,83,101,109,115,119,125, %T A088503 133,139,143,151,155,157,161,179,181,199,203,211,221,223,235,239,263, %U A088503 277,283,287,295,301,307,311,323,325,329,335,337,347,353,377,379,385 %N A088503 Numbers n such that (n^2 + 3)/4 is prime. %C A088503 Under Bunyakovsky's conjecture this sequence is infinite. - _Charles R Greathouse IV_, Dec 28 2011 %H A088503 Vincenzo Librandi, <a href="/A088503/b088503.txt">Table of n, a(n) for n = 1..1000</a> %F A088503 a(n) = 2*A002384(n) + 1 = sqrt(A110284(n)). - _Ray Chandler_, Sep 07 2005 %e A088503 (25*25 + 3)/4 = 157, 157 is prime, 25 is the 7th term of the sequence. %t A088503 Select[Range[500], PrimeQ[(#^2 + 3)/4] &] (* _Vincenzo Librandi_, Oct 06 2012 *) %o A088503 (PARI) for(k=2,1e3,if(isprime(k^2+k+1),print1(2*k+1", "))) \\ _Charles R Greathouse IV_, Dec 28 2011 %o A088503 (Magma) [n: n in [1..400 by 2] | IsPrime((n^2 + 3) div 4)]; // _Vincenzo Librandi_, Oct 06 2012 %Y A088503 Cf. A002383, A002384, A110284. %K A088503 easy,nonn %O A088503 1,1 %A A088503 _Pierre CAMI_, Nov 13 2003 %E A088503 Corrected and extended by _Ray Chandler_, Nov 16 2003