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 A178497 #16 Mar 11 2014 23:31:11
%S A178497 5,3,13,193,37633,1416317953,2005956546822746113,
%T A178497 4023861667741036022825635656102100993,
%U A178497 16191462721115671781777559070120513664958590125499158514329308740975788033
%N A178497 5 followed by A145503.
%C A178497 The first 6 entries of the sequence are primes.
%C A178497 The Fermat numbers F(.)=A000215(.) obey equations with flipped signs of the +-2 if compared with the a(n) (see the formula section): F(n) = Prod{i=0,...,n-1} F(i)+2 and F(n) = F(n-1) *(F(n-1)-2)+2. - _Vladimir Shevelev_, Dec 08 2010
%F A178497 a(n)= ( product_{i=0..n-1} a(i)) -2, n>=1.
%F A178497 a(n) = a(n-1)*( a(n-1)+2 )-2, n>=2. - _Vladimir Shevelev_, Dec 08 2010
%t A178497 Clear[a, n];
%t A178497 a[ -1] := 1; a[0] := 5;
%t A178497 a[n_] := a[n] = Product[a[i], {i, 0, n - 1}] - 2;
%t A178497 Table[a[n], {n, 0, 10}]
%Y A178497 Cf. A000215, A110407, A178428, A178427.
%K A178497 nonn
%O A178497 0,1
%A A178497 _Roger L. Bagula_, May 28 2010
%E A178497 Definition simplified by the Assoc. Eds. of the OEIS, Jun 07 2010