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 A195100 #36 Mar 23 2019 03:57:48 %S A195100 1,11,21,25,28,33,66,122,140,142,188,307,322,349,1007,1052 %N A195100 Numbers n such that there are no primes between (n-1)*sqrt(n-1) and n*sqrt(n). %C A195100 Cramér's conjecture implies that the sequence is finite. - _Robert Israel_, Aug 11 2014 %C A195100 No more terms up to 2*10^10. - _Jinyuan Wang_, Mar 22 2019 %H A195100 H. Cramér, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa2/aa212.pdf">On the order of magnitude of the difference between consecutive prime numbers</a>, Acta Arith. 2 (1936), 23-46. %F A195100 a(n+1) = A144140(n) + 1. - _Jinyuan Wang_, Mar 22 2019 %e A195100 a(1) = 1 because there are no numbers between (1-1)*sqrt(1-1) = 0 and 1*sqrt(1) = 1. %e A195100 a(2) = 11 because (11-1)*sqrt(11-1) < (nonprimes 32,33,34,35,36) < 11*sqrt(11). %p A195100 Primes:= select(isprime,{2,seq(2*i+1,i=1..10^6)}): %p A195100 C:= map(p -> ceil(p^(2/3)), Primes); %p A195100 {$1..max(C)} minus C; # _Robert Israel_, Aug 10 2014 %t A195100 Select[Range[5000], (PrimePi[# Sqrt[#]] - PrimePi[(# - 1)Sqrt[# - 1]]) == 0 &] (* _Alonso del Arte_, Sep 09 2011 *) %t A195100 Join[{1},Flatten[Position[Partition[Table[PrimePi[n Sqrt[n]],{n,1100}], 2,1], _?(#[[2]]-#[[1]]==0&),1,Heads->False]]+1] (* _Harvey P. Dale_, May 11 2018 *) %o A195100 (PARI) for(n=1,2*10^6,if(#primes([(n-1)*sqrt(n-1),n*sqrt(n)])==0,print1(n,", "))) \\ _Derek Orr_, Aug 10 2014 %o A195100 (PARI) isok(n) = {k=floor((n-1)*sqrt(n-1))+1;while(!isprime(k),k++);k>n*sqrt(n);} \\ _Jinyuan Wang_, Mar 22 2019 %Y A195100 Cf. A001223, A144140, A194852, A195008. %K A195100 nonn,more %O A195100 1,2 %A A195100 _Juri-Stepan Gerasimov_, Sep 09 2011