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 A181393 #12 Feb 10 2025 09:33:03
%S A181393 3,7,21,47,329,987,2207,103729,726103,2178309,4870847,10749959329,
%T A181393 505248088463,3536736619241,10610209857723,23725150497407,
%U A181393 115561578124843393729,255044402921529369959903,11987086937311880388115441,83909608561183162716808087,251728825683549488150424261
%N A181393 Numbers of the form Fibonacci(2^c)/Fibonacci(2^b), 1 <= b < c.
%C A181393 Using an Eratosthenes-like sieve, we find "primes" of the form P_k = Fibonacci(2^(k+1)) / Fibonacci(2^k) = A001566(k-1), k=1,2,..., such that every term has a unique "prime" factorization.
%F A181393 For n >= 1, a((n^2-n+2)/2) = P_n = A001566(n-1); for 1 <= m < k, a((k^2+3*k)/2-m) = Product_{i=m+1..k} A001566(i).
%e A181393 If k=3, m=1, by the latter formula, we have a(8) = A001566(2)*A001566(3) = 47*2207 = 103729.
%Y A181393 Cf. A000045, A001566.
%K A181393 nonn
%O A181393 1,1
%A A181393 _Vladimir Shevelev_, Oct 17 2010
%E A181393 a(12)-a(16) corrected and more terms from _Jason Yuen_, Feb 10 2025