

A065565


a(n) = floor((5/4)^n).


4



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, 264, 330, 413, 516, 646, 807, 1009, 1262, 1577, 1972, 2465, 3081, 3851, 4814, 6018, 7523, 9403, 11754, 14693, 18367, 22958, 28698, 35873, 44841, 56051, 70064, 87581
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,5


COMMENTS

a(n) is also the number of the circle curvature (rounded down) inscribing in 3:4:5 triangle arranged as spiral form. See illustration in links.  Kival Ngaokrajang, Aug 21 2013
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


LINKS



MATHEMATICA



PROG

(PARI) for (n=0, 400, write("b065565.txt", n, " ", floor((5/4)^n)) ) \\ Harry J. Smith, Oct 22 2009


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



