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A251295
Number of (n+1)X(3+1) 0..3 arrays with every 2X2 subblock summing to 3 6 or 9
1
2356, 22536, 223164, 2302844, 24846540, 280654684, 3313122288, 40698859196, 517132372168, 6752450899672, 90051946957152, 1220159586278176, 16726623359562940, 231245537389026104, 3216449699345556508
OFFSET
1,1
COMMENTS
Column 3 of A251300
LINKS
FORMULA
Empirical: a(n) = 70*a(n-1) -2063*a(n-2) +32707*a(n-3) -289660*a(n-4) +1236213*a(n-5) +63306*a(n-6) -20263462*a(n-7) +36944351*a(n-8) +154483968*a(n-9) -251174091*a(n-10) -887148665*a(n-11) -156301346*a(n-12) +1188162821*a(n-13) +919091600*a(n-14) -91672228*a(n-15) -237739072*a(n-16) -16658880*a(n-17) +16934400*a(n-18)
EXAMPLE
Some solutions for n=2
..1..2..1..0....1..2..1..0....3..2..3..0....1..1..2..0....0..0..3..3
..0..3..3..2....3..0..0..2....3..1..3..0....1..0..0..1....0..3..3..0
..3..3..0..1....1..2..1..0....0..2..3..0....2..0..3..2....3..3..0..0
CROSSREFS
Sequence in context: A063517 A035874 A226267 * A220626 A136420 A132391
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 01 2014
STATUS
approved