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A328921 Triangle read by rows: T(n,k) = number of vertex labeled connected Goldstone diagrams with n interactions and k external potentials.

%I A328921 #16 May 01 2021 22:25:46
%S A328921 1,2,1,20,8,1,592,240,36,2,33888,14208,2400,192,6,3134208,1355520,
%T A328921 248640,24000,1200,24,423974400,188052480,36599040,3978240,252000,
%U A328921 8640,120,78722795520,35613849600,7240020480,853977600,62657280,2822400,70560,720,19193652817920,8816953098240,1851920179200
%N A328921 Triangle read by rows: T(n,k) = number of vertex labeled connected Goldstone diagrams with n interactions and k external potentials.
%H A328921 R. J. Mathar, <a href="/A328921/a328921.mp.txt">Maple program computing A328921 - A328924</a>.
%H A328921 P. J. Rossky and M. Karplus, <a href="https://doi.org/10.1063/1.432387">The enumeration of Goldstone diagrams in many-body perturbation theory</a>, J. Chem. Phys. 64 (1976) 1569, C(n,k)
%F A328921 T(n,k) + A328922(n,k) = A328826(n,k).
%e A328921           1;
%e A328921           2           1;
%e A328921          20           8           1;
%e A328921         592         240          36           2;
%e A328921       33888       14208        2400         192           6;
%e A328921     3134208     1355520      248640       24000        1200          24;
%Y A328921 Cf. A328922, A328923, A328924.
%K A328921 nonn,tabl
%O A328921 0,2
%A A328921 _R. J. Mathar_, Oct 31 2019