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1,2
Column 1 of A196544
R. H. Hardin, Table of n, a(n) for n = 1..200
Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-3) +a(n-4).
Empirical: G.f. x*(x-1)*(x^2+3*x+1) / ( -1+x+x^2+3*x^3+x^4 ). - R. J. Mathar, Jul 25 2012
All solutions for n=4
..0....0....1....0....0....1....0
..2....1....0....2....2....1....2
..2....2....2....1....1....2....0
..0....0....0....1....0....0....1
Sequence in context: A049970 A104528 A177115 * A173099 A111928 A248054
Adjacent sequences: A196534 A196535 A196536 * A196538 A196539 A196540
nonn
R. H. Hardin Oct 03 2011
approved