%I A006129 M3678
%S A006129 1,0,1,4,41,768,27449,1887284,252522481,66376424160,34509011894545,
%T A006129 35645504882731588,73356937912127722841,301275024444053951967648,
%U A006129 2471655539737552842139838345,40527712706903544101000417059892
%N A006129 a(0),a(1),a(2),... satisfy Sum a(k) binomial(n,k) (k=0..n) = 2^binomial(n,
               2), for n=0.1,...
%C A006129 Also labeled graphs on n unisolated nodes (inverse binomial transform 
               of A006125).
%D A006129 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A006129 N. J. A. Sloane, <a href="transforms.txt">Transforms</a>
%F A006129 a(n)=sum_{k=0..n} (-1)^(n-k)*binomial(n, k)*2^binomial(k, 2).
%e A006129 2^binomial(n,2)=1+binomial(n,2)+4*binomial(n,3)+41*binomial(n,4)+768*binomial(n,
               5)+...
%Y A006129 Sequence in context: A134277 A085340 A001908 this_sequence A022515 A059730 
               A006825
%Y A006129 Adjacent sequences: A006126 A006127 A006128 this_sequence A006130 A006131 
               A006132
%K A006129 nonn,nice,easy
%O A006129 0,4
%A A006129 C. L. Mallows (colinm(AT)research.avayalabs.com)
%E A006129 More terms and additional comments from Vladeta Jovovic (vladeta(AT)eunet.rs), 
               Apr 09 2000