A085617 Number of nonisomorphic 2-graphs with 2n nodes with first cohomology invariant nonzero, second cohomology invariant 0.

0, 0, 2, 17, 392

Offset

1,3

Links

Table of n, a(n) for n=1..5.

F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.

F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.

Crossrefs

Cf. A006627, A002854.

Sequence in context: A319591 A198405 A202972 * A152557 A015202 A308864

Adjacent sequences: A085614 A085615 A085616 * A085618 A085619 A085620

Keyword

nonn

Author

N. J. A. Sloane, Jul 11 2003

Status

approved