Search: id:A000147
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%I A000147 M1741 N0690
%S A000147 0,0,0,0,0,1,2,7,14,32,58,110,187,322,519,839,1302,2015,3032,4542,6668,
%T A000147 9738,14006,20036,28324,39830,55473,76875,105692,144629,196585,266038,
%U A000147 357952,479664,639519,849425,1123191,1479972,1942284,2540674,3311415
%N A000147 Number of trees of diameter 5.
%C A000147 A tree of diameter 5 is formed from two rooted trees of height 2, with 
               their roots joined. - Frank Adams-Watters (FrankTAW(AT)Netscape.net), 
               Jan 13 2006
%D A000147 J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. 
               Dev. 4 (1960), 473-478.
%D A000147 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A000147 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A000147 <a href="Sindx_Tra.html#trees">Index entries for sequences related to 
               trees</a>
%F A000147 If n odd, a(n)=sum_{k=1}^{(n-1)/2} b(k)*b(n-k); if n even, a(n)=(sum_{k=1}^{n/
               2-1} b(k)*b(n-k)) + C(b(n/2)+1, 2), where b(n)=P(n-1)-1=A000065(n-1). 
               - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jan 13 2006
%Y A000147 Sequence in context: A034791 A140253 A018453 this_sequence A128902 A060552 
               A167762
%Y A000147 Adjacent sequences: A000144 A000145 A000146 this_sequence A000148 A000149 
               A000150
%K A000147 nonn
%O A000147 1,7
%A A000147 N. J. A. Sloane (njas(AT)research.att.com).
%E A000147 More terms from Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jan 13 
               2006

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