A198514 Consider a cellular automaton on the square grid where we start at time 1 with a finite collection of cells in state 1 and with all cells in state 0. At any time t, if a cell is in state 0 and the sum of the states of its neighborhood is t, the cell switches to state t. At any time t, if no cell switches to state t, the growth stops. The sequence gives the largest lifetime of any configuration starting from n cells which are rook connected.

1, 3, 6, 9, 11, 22, 22, 23, 29, 29, 35, 36, 36

Offset

1,2

Links

Table of n, a(n) for n=1..13.

Erich Friedman, Problem of the month September 2002

Example

The solution for n=4
  9 9
85 4 58
32 23
6311136
313
74 47
  8

Crossrefs

Cf. A198515, A198516.

Sequence in context: A101723 A353889 A113944 * A242088 A103695 A122809

Adjacent sequences: A198511 A198512 A198513 * A198515 A198516 A198517

Keyword

nonn,more

Author

Kausthub Gudipati, Oct 26 2011

Status

approved