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 A280689 #10 Jan 12 2017 07:18:24 %S A280689 1,1,1,1,1,2,1,3,2,5,1,4,1,13,5,7,1,17,1,11,13,89,1,18,5,233,17,29,1, %T A280689 122,1,47,89,1597,13,76,1,4181,233,123,1,842,1,199,122,28657,1,322,13, %U A280689 15005,1597,521,1,5777,89,843,4181,514229,1,1364,1,1346269,842,2207,233,39602,1,3571,28657,709805,1,5778,1,24157817,15005,9349,89,271442,1,15127,5777 %N A280689 a(n) = A000045(A032742(n)) / A000045(A054576(n)), where A000045(n) gives the n-th Fibonacci number, A032742(n) = the largest proper divisor of n, and A054576(n) = A032742(A032742(n)). %C A280689 A000045 is a divisibility sequence, which guarantees that the result of the division is an integer. %H A280689 Antti Karttunen, <a href="/A280689/b280689.txt">Table of n, a(n) for n = 1..987</a> %H A280689 Wikipedia, <a href="https://en.wikipedia.org/wiki/Divisibility_sequence">Divisibility sequence</a> %F A280689 a(n) = A105800(n) / A280688(n) = A105800(n) / A105800(A032742(n)). %F A280689 a(n) = A000045(A032742(n)) / A000045(A054576(n)). %F A280689 a(n) = A280690(A032742(n)). %o A280689 (Scheme) (define (A280689 n) (/ (A105800 n) (A280688 n))) %Y A280689 Cf. A000045, A032742, A054576, A105800, A280688, A280690, A280691. %K A280689 nonn %O A280689 1,6 %A A280689 _Antti Karttunen_, Jan 11 2017