A166537 Integers whose binary digits "1" define, if sorted into a quadrant shape whose right angle lies in a Go board corner, same colored Go stones that surely live all, but not if any stone is omitted

430, 441, 2262, 2534, 2546, 4494, 4518, 6493, 6494, 6510, 6521, 6522, 6598, 6627, 8982, 9102, 9116, 11206, 11218, 11220, 12974, 12979, 12982, 12985, 12988, 13190, 13197, 14969, 14974, 15078, 15092, 15182, 15194, 68758, 68764, 69030, 69042

Offset

1,1

Links

Table of n, a(n) for n=1..37.

Sensei's Library, Corner shapes

Example

2534 has the binary expansion 100111100110. Sorting into a quadrant shape (like in A165197, the least-significant digit into the corner) leads to:
0110
101
01
11
0
If the "0" top left is in a Go board corner and only the 7 digits "1" are Go stones of the same color, then all these 7 stones surely live, no matter where stones or chains of the other color with freedom(s) are. Removal of any of the 7 "1"-stones removes this sureness (for the remaining stones).

Crossrefs

Sequence in context: A227597 A321976 A147694 * A165058 A165062 A203545

Adjacent sequences: A166534 A166535 A166536 * A166538 A166539 A166540

Keyword

nonn,base

Author

Leonhard Kreissig, Oct 16 2009

Status

approved