A220568 Number of ways to reciprocally link elements of an 7Xn array either to themselves or to exactly one horizontal or antidiagonal neighbor.
1, 610, 27716, 3128843, 252139015, 22926570957, 1996515036228, 176531479976571, 15526120567015962, 1368042952494285120, 120466174602717968172, 10610162775514570773634, 934433508779628038701082
Offset: 1
Keywords
Examples
Some solutions for n=3 0=self 3=ne 4=w 6=e 7=sw (reciprocal directions total 10) ..0..7..7....0..0..0....6..4..0....0..0..0....0..7..0....6..4..0....6..4..0 ..3..3..7....0..7..0....6..4..0....0..6..4....3..6..4....0..7..0....0..0..7 ..0..3..0....3..6..4....0..6..4....0..6..4....0..7..0....3..6..4....0..3..0 ..6..4..0....0..7..0....0..0..7....0..6..4....3..6..4....0..6..4....0..6..4 ..6..4..7....3..6..4....0..3..0....6..4..0....0..0..0....0..0..0....0..7..0 ..0..3..7....6..4..0....0..0..0....6..4..7....0..7..7....6..4..0....3..6..4 ..0..3..0....0..0..0....0..0..0....0..3..0....3..3..0....0..0..0....6..4..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Comments