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 A049008 #3 Sep 13 2003 03:00:00 %S A049008 1,4,3,5,5,6,7,7,8,9,9,10,11,11,12,13,13,14,15,15,16,17,17,18,19,19, %T A049008 20,21,21,22,23,23,24,25,25,26,27,27,28,29,29,30,31,31,32,33,33,34,35, %U A049008 35,36,37,37,38,39,39,40,41,41,42,43,43,44,45,45,46,47,47,48,49,49,50 %N A049008 Greatest possible number of right angles that can occur as interior angles in a planar n-gon. %C A049008 Reflex angles (e.g. 270 degrees) are not considered right angles. From a(6) on, this duplicates A004396 from its eighth term. %F A049008 a(3) = 1; a(4) = 4; a(5) = 3; a(3*k+3) = 2*k+3; a(3*k+4) = 2*k+3; a(3*k+5) = 2*k+4 where k starts from 1 OR a(n) is the greatest integer less than 2/3*(n+2) where n starts from 6. %e A049008 a(3) = 1 because you can only have one right angle in a triangle; a(4) = 4 as in a rectangular quadrilateral; a(100) = 67 etc. %Y A049008 Cf. A004396. %K A049008 easy,nonn %O A049008 3,2 %A A049008 Deepak R. N (deepak_rama(AT)bigfoot.com)