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 A073272 #14 Sep 08 2022 08:45:06
%S A073272 0,1,0,3,-1,3,-1,0,5,-3,3,3,-1,-1,1,5,-3,3,3,-3,3,-1,-1,5,3,-1,3,-1,
%T A073272 -9,11,-1,5,-7,9,-3,1,3,-1,1,5,-7,9,-1,3,-9,1,9,3,-1,-1,5,-7,5,1,1,5,
%U A073272 -3,3,3,-7,-3,11,3,-1,-9,9,-3,9,-1,-1,-1,3,1,3,-1,-1,5,-3,-1,9,-7,9,-3,3,-1
%N A073272 A000040(n+1) - A073271(n).
%C A073272 Observation/conjecture: a(n)=0 iff A073271(n) in {3, 7, 23}.
%H A073272 Charles R Greathouse IV, <a href="/A073272/b073272.txt">Table of n, a(n) for n = 1..10000</a>
%e A073272 For n=11, A000040(11)*A000040(13)/A000040(12) = 31*41/37 = 1271/37 = (34*37+13)/37, therefore A073271(11)=34; a(11) = A000040(12)-A073271(11) = 37-34 = +3.
%t A073272 Table[Prime[n+1] - Floor[Prime[n] Prime[n+2] / Prime[n+1]], {n, 80}] (* _Vincenzo Librandi_, May 31 2015 *)
%o A073272 (Magma) [NthPrime(n+1)-Floor(NthPrime(n)*NthPrime(n+2) / NthPrime(n+1)): n in [1..80]]; // _Vincenzo Librandi_, May 31 2015
%o A073272 (PARI) a(n,p=prime(n))=my(q=nextprime(p+1),r=nextprime(q+1)); q - p*r\q \\ _Charles R Greathouse IV_, Jun 02 2015
%Y A073272 Cf. A073274.
%K A073272 sign
%O A073272 1,4
%A A073272 _Reinhard Zumkeller_, Jul 22 2002