%I #38 May 18 2024 23:43:42
%S 1,1,1,1,2,3,3,4,5,7,9,11,14,18,22,28,35,44,55,69,86,108,135,169,211,
%T 264,330,413,516,646,807,1009,1262,1577,1972,2465,3081,3851,4814,6018,
%U 7523,9403,11754,14693,18367,22958,28698,35873,44841,56051,70064,87581
%N a(n) = floor((5/4)^n).
%C a(n) is also the curvature (rounded down) of the circle inscribed in the n-th 3:4:5 triangle arranged in a spiral as shown in the illustration in the links section. - _Kival Ngaokrajang_, Aug 21 2013
%C By the result of Dubickas and Novikas, a(n) is divisible by at least one of 2, 3, 7, 11, 13 infinitely often, so that a(n) is composite infinitely often. - _Tomohiro Yamada_, Apr 23 2017
%H Harry J. Smith, <a href="/A065565/b065565.txt">Table of n, a(n) for n = 0..400</a>
%H Arturas Dubickas, Aivaras Novikas, <a href="https://doi.org/10.1007/s00209-005-0827-4">Integer parts of powers of rational numbers</a>, Math. Z. 251 (2005), 635-648, available from <a href="http://www.mif.vu.lt/~dubickas/files/dvifai/suaivaru.pdf">the first author's page</a>.
%H Kival Ngaokrajang, <a href="/A065565/a065565.jpg">Illustration of some initial terms</a>.
%t Table[ Floor[(5/4)^n], {n, 0, 41}] (* _Robert G. Wilson v_, May 26 2004 *)
%o (PARI) for (n=0, 400, write("b065565.txt", n, " ", floor((5/4)^n)) ) \\ _Harry J. Smith_, Oct 22 2009
%Y Cf. A002379, A094969-A094500.
%Y Cf. A064628. - _Tomohiro Yamada_, Apr 23 2017
%K nonn
%O 0,5
%A _Benoit Cloitre_, Nov 30 2001
%E Edited by _N. J. A. Sloane_ at the suggestion of _Stefan Steinerberger_, Jun 20 2007
%E Offset changed from 1 to 0 by _Harry J. Smith_, Oct 22 2009