# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a211990 Showing 1-1 of 1 %I A211990 #29 Mar 11 2014 01:34:20 %S A211990 1,1,2,1,2,3,2,3,4,5,2,4,5,6,7,4,6,8,9,10,11,4,8,10,12,13,14,15,7,11, %T A211990 15,17,19,20,21,22,8,15,19,23,25,27,28,29,30,12,20,27,31,35,37,39,40, %U A211990 41,42,14,26,34,41,45,49,51,53,54,55,56,21,35,47 %N A211990 Triangle read by rows: T(n,k) = total number of regions in the last k shells of n. %C A211990 For the definition of "region of n" see A206437. For the definition of "last section of n" see A135010. %C A211990 Apparently differs from A027300 at the right border. %H A211990 Omar E. Pol, Illustration of the seven regions of 5 %F A211990 T(n,k) = A000041(n) - A000041(n-k), if 1= 1. %Y A211990 Cf. A027300, A135010, A138121, A182703, A186114, A206437, A212010, A212011. %K A211990 nonn,tabl %O A211990 1,3 %A A211990 _Omar E. Pol_, Apr 27 2012 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE