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 A195008 #33 Apr 02 2025 22:07:37
%S A195008 1,24,36,47,93,105,109,117,122,207,627,996
%N A195008 Numbers k such that there are no primes between k*sqrt(k-1) and (k+1)*sqrt(k).
%C A195008 Numbers k such that there are only nonprimes between k*sqrt(k-1) and (k+1)*sqrt(k).
%C A195008 No more terms up to 100000. - _Franklin T. Adams-Watters_, Sep 08 2011
%C A195008 No more terms up to 364821. - _J.W.L. (Jan) Eerland_, Jan 21 2025
%e A195008 a(1)=1 because 1*sqrt(1-1)=0<(nonprime 1)<(1+1)*sqrt(1)=2,
%e A195008 a(2)=24 because 24*sqrt(24-1)<(nonprimes 116,117,118,119,120,121,122)<(24+1)*sqrt(24).
%t A195008 Join[{1},Select[Range[1000],PrimePi[# Sqrt[#-1]]==PrimePi[(#+1)Sqrt[#]]&]] (* _Harvey P. Dale_, Jun 01 2018 *)
%o A195008 (PARI) isa(n)=if(n<=1,n==1,primepi(floor(n*sqrt(n-1)))==primepi(floor((n+1)*sqrt(n))))
%Y A195008 Cf. A195007.
%K A195008 nonn,more,hard
%O A195008 1,2
%A A195008 _Juri-Stepan Gerasimov_, Sep 07 2011
%E A195008 a(11) and a(12) from _Franklin T. Adams-Watters_, Sep 08 2011