%I A030236
%S A030236 1,2,7,18,49,136,377,1044,2891,8006,22171,61398,170029,470860,1303949,
%T A030236 3611016,9999959,27692810,76689487,212375610,588130153,1628704336,
%U A030236 4510358465,12490501212,34589849507,95789405774,265268869027
%N A030236 Cycle-path coverings of a family of digraphs.
%D A030236 O. M. D'Antona and E. Munarini, The Cycle-path Indicator Polynomial of 
               a Digraph, Advances in Applied Mathematics 25 (2000), 41-56.
%F A030236 a(n+4) = 3 a(n+3) - a(n+2) + a(n+1), n >= 0; a(n+3) = 2*a(n+2) + a(n+1) 
               + 2*sum( a(i), i = 0..n ), n >= 0; G.f.: (1-t+2*t^2-2*t^3)/(1-3*t+t^2-t^3)
%Y A030236 Cf. A030186.
%Y A030236 Sequence in context: A072338 A022726 A017925 this_sequence A074141 A122931 
               A094976
%Y A030236 Adjacent sequences: A030233 A030234 A030235 this_sequence A030237 A030238 
               A030239
%K A030236 nonn,easy
%O A030236 0,2
%A A030236 Ottavio D'Antona (dantona(AT)dsi.unimi.it) and Emanuele Munarini (munarini(AT)mate.polimi.it).