A085619 Number of 2-graphs with n nodes and integral spectrum.

2, 2, 4, 8, 9, 16

Offset

4,1

Links

Table of n, a(n) for n=4..9.

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. A002854.

Sequence in context: A132007 A094605 A217662 * A085620 A325867 A333045

Adjacent sequences: A085616 A085617 A085618 * A085620 A085621 A085622

Keyword

nonn

Author

N. J. A. Sloane, Jul 11 2003

Status

approved