A328921 Triangle read by rows: T(n,k) = number of vertex labeled connected Goldstone diagrams with n interactions and k external potentials.
1, 2, 1, 20, 8, 1, 592, 240, 36, 2, 33888, 14208, 2400, 192, 6, 3134208, 1355520, 248640, 24000, 1200, 24, 423974400, 188052480, 36599040, 3978240, 252000, 8640, 120, 78722795520, 35613849600, 7240020480, 853977600, 62657280, 2822400, 70560, 720, 19193652817920, 8816953098240, 1851920179200
Offset: 0
Examples
1; 2 1; 20 8 1; 592 240 36 2; 33888 14208 2400 192 6; 3134208 1355520 248640 24000 1200 24;
Links
- R. J. Mathar, Maple program computing A328921 - A328924.
- P. J. Rossky and M. Karplus, The enumeration of Goldstone diagrams in many-body perturbation theory, J. Chem. Phys. 64 (1976) 1569, C(n,k)