Search: id:A036657 Results 1-1 of 1 results found. %I A036657 %S A036657 0,0,0,1,1,3,5,12,23,52,109,244,532,1196,2671,6055,13726,31380, %T A036657 71901,165635,382610,887215,2062777,4810230,11243898,26346341,61863991, %U A036657 145560102,343121676,810246372,1916417479,4539722153,10769366928 %N A036657 Number of n-node rooted unlabeled trees with out-degree <=2 and exactly 2 edges at the root. %D A036657 S. J. Cyvin et al., Enumeration of constitutional isomers of polyenes, J. Molec. Structure (Theochem), 357 (1995), 255-261. %H A036657 Index entries for sequences related to rooted trees %F A036657 G.f. satisfies A(x) = (W(x)-x)*(1-x)/x-x, where W(x) is g.f. for A001190. %p A036657 N := 40: G036657 := series(G001190*(1/x-1)-1,x,N); A036657 := n->coeff(G036657, x,n); %Y A036657 First differences of A001190. %Y A036657 Sequence in context: A161624 A034758 A131322 this_sequence A047761 A026786 A027246 %Y A036657 Adjacent sequences: A036654 A036655 A036656 this_sequence A036658 A036659 A036660 %K A036657 nonn %O A036657 0,6 %A A036657 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.001 seconds