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 A111431 #13 Jul 21 2021 07:12:18 %S A111431 0,0,1,1,1,3,13,233,46368,701408733,37889062373143906, %T A111431 6161314747715278029583501626149, %U A111431 818706854228831001753880637535093596811413714795418360007 %N A111431 a(n) = Fibonacci(tribonacci(n)). %H A111431 Alois P. Heinz, <a href="/A111431/b111431.txt">Table of n, a(n) for n = 0..16</a> %F A111431 a(n) = A000045(A000073(n)). %e A111431 a(0) = Fibonacci(tribonacci(0)) = A000045(A000073(0)) = A000045(0) = 0. %e A111431 a(1) = Fibonacci(tribonacci(1)) = A000045(A000073(1)) = A000045(0) = 0. %e A111431 a(2) = Fibonacci(tribonacci(2)) = A000045(A000073(2)) = A000045(1) = 1. %e A111431 a(3) = Fibonacci(tribonacci(3)) = A000045(A000073(3)) = A000045(1) = 1. %e A111431 a(4) = Fibonacci(tribonacci(4)) = A000045(A000073(4)) = A000045(2) = 1. %e A111431 a(5) = Fibonacci(tribonacci(5)) = A000045(A000073(5)) = A000045(4) = 3. %e A111431 a(6) = Fibonacci(tribonacci(6)) = A000045(A000073(6)) = A000045(7) = 13. %e A111431 a(7) = Fibonacci(tribonacci(7)) = A000045(A000073(7)) = A000045(13) = 233. %e A111431 a(8) = A000045(A000073(8)) = A000045(24) = 46368. %e A111431 a(9) = A000045(A000073(9)) = A000045(44) = 701408733. %e A111431 a(10) = A000045(A000073(10)) = A000045(81) = 37889062373143906. %p A111431 a:= n-> (<<0|1>, <1|1>>^((<<0|1|0>, <0|0|1>, <1|1|1>>^n)[1, 3]))[1, 2]: %p A111431 seq(a(n), n=0..13); # _Alois P. Heinz_, Aug 09 2018 %t A111431 Fibonacci/@LinearRecurrence[{1,1,1},{0,0,1},15] (* _Harvey P. Dale_, Jan 04 2013 *) %Y A111431 Cf. A000045, A000073, A066178, A007570, A111425. %K A111431 easy,nonn %O A111431 0,6 %A A111431 _Jonathan Vos Post_, Nov 13 2005