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 A029846 #10 Mar 16 2017 19:28:30 %S A029846 1,3,5,7,23,347,109307,11878938227,141106591489900388627, %T A029846 19911070158545297149320104511797515190627, %U A029846 396450714858513044552818188364610837019759458190194070051140109393414330800390627 %N A029846 a(n) = a(n-1)*b(n-2)+2, b() given by A029758. %D A029846 D. E. Knuth, Art of Computer Programming, Vol. 3, Sect. 6.2.3 (7) and (8). %H A029846 Alois P. Heinz, <a href="/A029846/b029846.txt">Table of n, a(n) for n = 0..13</a> %o A029846 (PARI) a(n)=if(n<3,max(0,1+2*n),2+a(n-1)*(a(n-1)-2)*(a(n-2)-2)/a(n-2)) /* _Michael Somos_, Feb 07 2004 */ %K A029846 easy,nonn %O A029846 0,2 %A A029846 _Don Knuth_ %E A029846 More terms from _N. J. A. Sloane_