A085600 Number of simple graphs with 3 edges on n unlabeled vertices.

0, 0, 1, 3, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5

Offset

1,4

Links

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1).

Formula

a(n) = 5 for n >= 6.

Prog

(PARI) a(n) = if(n<6, if(n>=3, [1, 3, 4][n-2], 0), 5) \\ Andrew Howroyd, Oct 29 2025

Crossrefs

Cf. A000088.

Sequence in context: A319460 A343528 A161386 * A128999 A220854 A122816

Adjacent sequences: A085597 A085598 A085599 * A085601 A085602 A085603

Keyword

nonn,easy

Author

Jon Perry, Jul 06 2003

Status

approved