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 A186751 #15 Nov 21 2013 12:50:08 %S A186751 3,5,21,437,190965,36467631221,1329888126870853950837, %T A186751 1768602429992068534155014726612412013000565 %N A186751 a(0) = 3; thereafter, a(n) = a(n-1)^2 - 4. %C A186751 This is to A001566 as 4 is to 2 (subtrahend). This is the k=4 row of the array A[k,0] = 3, A[k,n] = A[k,n-1]^2 - k; A186750 is the k=3 row; and A001566 is the k=2 row. A003096(n+1) is the k=1 row. %e A186751 a(1) = a(0)^2 - 4 = 3^2 - 4 = 5, which is, like a(0), a prime. %t A186751 NestList[#^2-4&,3,10] (* _Harvey P. Dale_, Mar 14 2011 *) %Y A186751 Cf. A001566, A003096, A186750. %K A186751 nonn,easy %O A186751 0,1 %A A186751 _Jonathan Vos Post_, Feb 26 2011