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 A080680 #10 Jun 04 2023 13:02:42 %S A080680 2,3,4,5,6,6,7,7,8,9,9,10,10,10,11,12,12,13,13,13,14,15,15,15,16,16, %T A080680 16,16,17,17,17,18,18,18,19,19,19,20,20,20,20,21,21,21,22,22,23,23,23, %U A080680 24,24,24,24,24,25,25,25,25,26,26,26,27,27,27,27,27,28,28,28,28,29,29,29 %N A080680 Integer part of the square root of the n-th prime of the form 4k+1. %C A080680 a(n)^2 < A002330(n+2)^2 + A002331(n+2)^2 < a(n+1)^2. %F A080680 a(n) = A000196(A002144(n)). %t A080680 Floor[Sqrt[#]]&/@Select[Prime[Range[300]],Mod[#,4]==1&] (* _Harvey P. Dale_, Jun 04 2023 *) %K A080680 nonn %O A080680 1,1 %A A080680 _Reinhard Zumkeller_, Mar 02 2003