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A281562
Number of nX7 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1
0, 2180, 16656, 67834, 243040, 692421, 1818257, 4578736, 11105124, 26461889, 62339543, 144976485, 333721541, 763157635, 1734158357, 3916675838, 8803744638, 19704291923, 43922013234, 97556616406, 215997549807, 476806559336
OFFSET
1,2
COMMENTS
Column 7 of A281563.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -7*a(n-2) +10*a(n-3) -38*a(n-4) +34*a(n-5) +7*a(n-6) +88*a(n-7) -38*a(n-8) -170*a(n-9) -101*a(n-10) -17*a(n-11) +372*a(n-12) +141*a(n-13) +120*a(n-14) -163*a(n-15) -310*a(n-16) -331*a(n-17) -391*a(n-18) +389*a(n-19) +548*a(n-20) +414*a(n-21) -66*a(n-22) -180*a(n-23) -106*a(n-24) -499*a(n-25) -184*a(n-26) +235*a(n-27) +274*a(n-28) +37*a(n-29) -27*a(n-30) +90*a(n-31) -81*a(n-32) -108*a(n-33) +27*a(n-34) +27*a(n-35) for n>58
EXAMPLE
Some solutions for n=4
..0..0..1..0..1..0..0. .0..1..1..0..1..0..1. .0..1..0..0..1..0..0
..1..0..1..1..1..0..0. .0..1..1..0..1..0..0. .0..1..1..0..1..0..1
..1..0..1..0..0..1..0. .0..1..0..1..0..1..1. .0..0..1..0..1..1..0
..1..0..1..1..0..1..1. .1..0..0..1..0..1..0. .1..1..1..0..0..1..1
CROSSREFS
Cf. A281563.
Sequence in context: A137875 A020425 A253519 * A254417 A254424 A343777
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 24 2017
STATUS
approved