Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #13 Nov 18 2012 12:34:32
%S 1,3,4,6,8,8,10,14,16,17,20,23,22,22,28,32,30,31,36,37,36,40,46,46,44,
%T 47,50,51,54,58,60,60,60,61,64,69,72,72,74,76,74,75,82,87,86,86,90,90,
%U 88,93,100,101,100,102,104,104,106,111,114,115,116,116,118,122
%N Coordination sequence for VPl-5 structure with respect to node (X) where 18-gon and two squares meet.
%C There are two types of nodes in this structure.
%C The coordination sequence with respect to a particular node gives the number of nodes that can be reached from that node in n steps along edges.
%H Joseph Myers, <a href="/A072152/b072152.txt">Table of n, a(n) for n = 0..1000</a>
%H M. E. Davis, <a href="http://dx.doi.org/10.1038/nature00785">Ordered porous materials for emerging applications</a>, Nature, 417 (Jun 20 2002), 813-821 (gives structure).
%H N. J. A. Sloane, <a href="/A072152/a072152.gif">VPl-5 structure, after Davis</a>
%F Empirical G.f.: -(x^17+x^16-x^15-2*x^14-2*x^13-2*x^12-4*x^11-5*x^10-5*x^9-5*x^8-7*x^7-6*x^6-4*x^5-4*x^4-4*x^3-2*x^2-2*x-1)/((x-1)^2*(x^2+1)*(x^4+1)*(x^6+x^5+x^4+x^3+x^2+x+1)). [_Colin Barker_, Nov 18 2012]
%Y Cf. A072149-A072154.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, Jun 28 2002
%E Extended by _Joseph Myers_, Sep 30 2011