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 A103815 #20 Aug 29 2021 17:04:13
%S A103815 0,0,1,5,29,239,3119,65519,2227679,122522399,10904493599,
%T A103815 1570247078399,365867569267199,137932073613734399,
%U A103815 84138564904377983999,83044763560621070207999,132622487406311849122175999,342696507457909818131702783999,1432814097681520949608649339903999
%N A103815 a(n) = -1 + Product_{k=1..n} Fibonacci(k).
%C A103815 a(n) asymptotic to Phi^A000217(n). Prime for n = 4, 5, 6, 7, 8, 14, 15. Semiprime for n = 9, 10, 11, 20.
%C A103815 Thus, it is not until the 12th element in the sequence that we get number with more than 2 prime factors: 1570247078399 = 37 * 59 * 16349 * 43997. - _Jonathan Vos Post_, Dec 08 2012
%H A103815 Harvey P. Dale, <a href="/A103815/b103815.txt">Table of n, a(n) for n = 1..99</a>
%F A103815 a(n) = Product[Fibonacci[k], {k, 1, n}]-1 = Product[A000045[k], {k, 1, n}]-1.
%F A103815 a(n) = A003266(n) - 1. - _Alois P. Heinz_, Aug 09 2018
%e A103815 a(15) = 1 * 1 * 2 * 3 * 5 * 8 * 13 * 21 * 34 * 55 * 89 * 144 * 233 * 377 * 610 - 1 = 84138564904377983999 is prime.
%p A103815 F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:
%p A103815 a:= n-> -1 + mul(F(i), i=1..n):
%p A103815 seq(a(n), n=1..20); # _Alois P. Heinz_, Aug 09 2018
%t A103815 FoldList[Times,Fibonacci[Range[20]]]-1 (* _Harvey P. Dale_, Aug 29 2021 *)
%Y A103815 Cf. A000045, A000217, A003266, A052449, A053413, A053408.
%K A103815 easy,nonn
%O A103815 1,4
%A A103815 _Jonathan Vos Post_, Mar 29 2005