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 A163161 #7 Aug 13 2025 21:53:12
%S A163161 5,9,14,30,44,47,64,67,72,89,99,124,125,194,198,200,208,213,214,249,
%T A163161 267,270,320,333,372,373,374,393,455,460,475,519,586,603,643,701,704,
%U A163161 712,770,774,789,814,825,828,836,891,906,930,941,970,974,982,983,988,1022
%N A163161 Values of n at which the sequence A161865/A161867 equals 1/2.
%C A163161 The corresponding sequence for primes is A144264, and the ratio is given by sequences A161621/A161622.
%t A163161 t1 = Table[ ((2n+1) - (PrimePi[(n+1)^2] - PrimePi[n^2]))/((4n+4)- (PrimePi[(n+2)^2] - PrimePi[n^2])), {n,1,300}]; t2= Position[t1, 1/2] (* _Daniel Tisdale_, Jul 24 2009 *)
%K A163161 nonn
%O A163161 1,1
%A A163161 _Daniel Tisdale_, Jul 21 2009, Jul 24 2009
%E A163161 Corrected by the author, Jul 25 2009
%E A163161 Extended beyond 194 by _R. J. Mathar_, Sep 27 2009