A243205 Consider the n X n Go board as a graph; remove i nodes and let j be the number of nodes in the largest connected subgraph remaining; then a(n) = minimum (i + j).

1, 3, 5, 9, 12, 16, 20, 25, 29

Offset

1,2

Comments

I believe the next terms are 36, 41, 47, ...

Links

Table of n, a(n) for n=1..9.

Gordon Hamilton, Termite Terrorists: Children working on this problem in grade 2 classrooms. Published on YouTube.com, Jan 01 2013.

Example

a(10) <= 36 because i + j = 18 + 18 = 36 in the left graph and i + j = 23 + 13 = 36 in the right graph. 36 may be the minimum.
-----X----   -----X----
----X-----   -----X----
---X-X----   ---XX-X---
--X---X---   XXX----X--
-X-----X-X   ---X----XX
X-X-----X-   ----X--X--
---X---X--   ---X-X-X--
----X-X---   --X---X---
-----X----   -X----X---
----X-----   X-----X---

Crossrefs

Sequence in context: A061562 A006282 A086845 * A259368 A175098 A351389

Adjacent sequences: A243202 A243203 A243204 * A243206 A243207 A243208

Keyword

more,nonn

Author

Gordon Hamilton, Jun 01 2014

Extensions

Edited by N. J. A. Sloane, Jun 02 2014

Minor edits by M. F. Hasler, Mar 21 2015

Status

approved