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 A094189 #31 Apr 21 2025 11:26:42
%S A094189 0,2,1,1,1,1,2,2,2,1,1,2,3,2,2,2,3,4,4,3,4,3,3,4,5,4,3,4,5,4,4,5,4,4,
%T A094189 5,5,2,6,6,5,4,6,4,5,7,7,3,7,8,4,5,10,7,5,6,5,5,10,7,8,8,6,10,7,5,5,8,
%U A094189 7,7,5,10,7,8,10,7,7,10,10,9,12,7,11,10,10,9,7,13,11,10,10,11,10,11,10,11
%N A094189 Number of primes between n^2-n and n^2 (inclusive).
%C A094189 Conjecture: for n>11, a(n)>1.
%C A094189 Oppermann conjectured in 1882 that a(n)>0 for n>1. - _T. D. Noe_, Sep 16 2008
%D A094189 Paulo Ribenboim, The New Book of Prime Number Records, 3rd ed., 1995, Springer, p. 248.
%D A094189 Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 183.
%H A094189 T. D. Noe, <a href="/A094189/b094189.txt">Table of n, a(n) for n = 1..10000</a>
%H A094189 Wikipedia, <a href="http://en.wikipedia.org/wiki/Oppermann%27s_conjecture">Oppermann's conjecture</a>
%t A094189 Table[PrimePi[n^2]-PrimePi[n^2-n-1],{n,100}] (* _Harvey P. Dale_, Jul 24 2015 *)
%o A094189 (PARI) a(n) = sum(k=n^2-n,n^2,isprime(k))
%o A094189 (PARI) a(n)=my(s);forprime(p=n^2-n,n^2,s++);s \\ _Charles R Greathouse IV_, Jan 18 2016
%o A094189 (Haskell)
%o A094189 a094189 n = sum $ map a010051' [n*(n-1) .. n^2]
%o A094189 -- _Reinhard Zumkeller_, Jun 07 2015
%Y A094189 Cf. A014085, A089610, A108309, A010051.
%K A094189 easy,nonn
%O A094189 1,2
%A A094189 _Jason Earls_, May 25 2004