|
Search: id:A079316
|
|
|
| A079316 |
|
Number of first-quadrant cells (including the two boundaries) That are ON at stage n of the cellular automaton described in A079317. |
|
+0
4
|
|
| 1, 3, 3, 7, 5, 11, 9, 21, 11, 25, 15, 35, 19, 45, 29, 73, 31, 77, 35, 87, 39, 97, 49, 125, 53, 135, 63, 163, 73, 191, 101, 273, 103, 277, 107, 287, 111, 297, 121, 325, 125, 335, 135, 363, 145, 391, 173, 473, 177, 483, 187, 511, 197, 539, 225, 621, 235, 649, 263, 731
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Start with cell (0,0) active; at each succeeding stage the cells that share exactly one edge with an active cell change their state.
The pattern has 4-fold symmetry; sequence just counts cells in one quadrant.
This is not the CA discussed by Singmaster in the reference given in A079314. That was an error based on my misreading of the paper. - N. J. A. Sloane, Aug 05 2009
|
|
FORMULA
|
This is not the CA discussed by Singmaster in the reference given in A079314. That was an error based on my misreading of the paper. - N. J. A. Sloane, Aug 05 2009
|
|
PROGRAM
|
(PARI) M=matrix(101, 101); M[1, 1]=1; for(s=1, 100, c=[]; a=M[1, 1]; for(x=2, 100, for(y=2, 100, a+=M[x, y]; if(M[x-1, y]+M[x+1, y]+M[x, y-1]+M[x, y+1]==1, c=concat(c, [[x, y]]) )); a+=M[x, 1]+M[1, x]; if(M[x, 2]==0 && M[x-1, 1]+M[x+1, 1]==1, c=concat(c, [[x, 1]]) ); if(M[2, x]==0 && M[1, x-1]+M[1, x+1]==1, c=concat(c, [[1, x]]) )); print1(a, ", "); for(i=1, length(c), M[c[i][1], c[i][2]]=1-M[c[i][1], c[i][2]]) ) - Max Alekseyev (maxale(AT)gmail.com), Feb 02 2007
|
|
CROSSREFS
|
Cf. A079317, A151922, A151923.
Sequence in context: A085379 A070801 A114753 this_sequence A106481 A106477 A098043
Adjacent sequences: A079313 A079314 A079315 this_sequence A079317 A079318 A079319
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Feb 12 2003
|
|
EXTENSIONS
|
More terms from Max Alekseyev (maxale(AT)gmail.com), Feb 02 2007
Edited by N. J. A. Sloane, Aug 05 2009
|
|
|
Search completed in 0.002 seconds
|
