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 A065566 #21 Dec 09 2024 22:03:51
%S A065566 7,15,17,21,25,34,52,56,59,68,74,78,99,104,111,117,118,119,124,127,
%T A065566 129,135,136,141,145,157,162,172,179,181,184,189,190,203,204,206,209,
%U A065566 211,212,222,226,228,245,247,250,256,258,283,291,302,315,318,327,328,331
%N A065566 Numbers k such that floor((5/4)^(k+1))/floor((5/4)^k) = 5/4.
%C A065566 Also, numbers k such that (5^(k+1) mod 4^(k+1))/(5^k mod 4^k)=5, or A138589(n+1)/A138589(n) = 5. (See the Mathar link in A139768.)
%H A065566 Zak Seidov, <a href="/A065566/b065566.txt">Table of n, a(n) for n = 1..1000</a>
%F A065566 Is it true that lim_{n->infinity} a(n)/n = 6?
%o A065566 (PARI) isok(k) = { my(f=5/4); floor(f^(k + 1))/floor(f^k) == f } \\ _Harry J. Smith_, Oct 22 2009
%Y A065566 Cf. A065554, A138589, A139768.
%K A065566 nonn
%O A065566 1,1
%A A065566 _Benoit Cloitre_, Nov 30 2001
%E A065566 More terms from _Jason Earls_, Dec 03 2001
%E A065566 Edited by _N. J. A. Sloane_, May 24 2008