Number of symmetric polynomial functions of degree n of a symmetric matrix (of indefinitely large size) under joint row and column permutations. Also number of multigraphs with n edges (allowing loops) on an infinite set of nodes.
A007717
Number of symmetric polynomial functions of degree n of a symmetric matrix (of indefinitely large size) under joint row and column permutations. Also number of multigraphs with n edges (allowing loops) on an infinite set of nodes.
Terms
- a(0) =1a(1) =2a(2) =7a(3) =23a(4) =79a(5) =274a(6) =1003a(7) =3763a(8) =14723a(9) =59663a(10) =250738a(11) =1090608a(12) =4905430a(13) =22777420a(14) =109040012a(15) =537401702a(16) =2723210617a(17) =14170838544a(18) =75639280146a(19) =413692111521
External references
- oeis: A007717