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A317892
Number of nX4 0..1 arrays with every element unequal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
0, 2, 13, 82, 549, 3697, 25169, 170608, 1156219, 7839519, 53154565, 360388169, 2443433405, 16566593998, 112322259076, 761549454562, 5163336422278, 35007634908875, 237353212759913, 1609264585122172, 10910880368099881
OFFSET
1,2
COMMENTS
Column 4 of A317896.
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) -31*a(n-2) +92*a(n-3) -221*a(n-4) +144*a(n-5) -125*a(n-6) -169*a(n-7) +1231*a(n-8) +2495*a(n-9) -3384*a(n-10) +5083*a(n-11) -5257*a(n-12) -28179*a(n-13) -6771*a(n-14) +3549*a(n-15) -14557*a(n-16) +77495*a(n-17) +143971*a(n-18) +91139*a(n-19) +96950*a(n-20) -44694*a(n-21) -239000*a(n-22) -395274*a(n-23) -505737*a(n-24) -331428*a(n-25) -184844*a(n-26) +98400*a(n-27) +220028*a(n-28) +618689*a(n-29) +734341*a(n-30) +885867*a(n-31) +765523*a(n-32) +563084*a(n-33) +149323*a(n-34) -95273*a(n-35) -323108*a(n-36) -344668*a(n-37) -268599*a(n-38) -148723*a(n-39) -57429*a(n-40) +36378*a(n-41) +53163*a(n-42) +30807*a(n-43) +14338*a(n-44) +6375*a(n-45) -2291*a(n-46) -2889*a(n-47) -702*a(n-48) -238*a(n-49) -97*a(n-50) +2*a(n-51) +19*a(n-52) -4*a(n-54) for n>56
EXAMPLE
Some solutions for n=5
..0..1..0..0. .0..1..0..0. .0..1..0..0. .0..1..0..1. .0..1..0..0
..1..0..1..1. .1..0..1..1. .1..1..1..1. .1..0..1..0. .1..1..1..1
..0..1..1..0. .0..1..1..0. .0..0..0..0. .1..0..1..1. .0..0..0..0
..0..1..0..1. .0..0..0..1. .1..0..0..1. .0..0..1..0. .1..1..1..1
..1..0..1..0. .1..1..1..0. .1..0..1..0. .1..1..0..1. .0..0..1..0
CROSSREFS
Cf. A317896.
Sequence in context: A074581 A020059 A162772 * A079752 A156018 A285795
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 10 2018
STATUS
approved