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A298795
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Coordination sequence for the bil tiling (or net) with respect to a trivalent node of the fourth type.
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4
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1, 3, 6, 8, 11, 16, 19, 18, 23, 30, 29, 30, 35, 42, 43, 40, 47, 52, 55, 56, 55, 64, 67, 68, 71, 72, 79, 78, 83, 90, 85, 90, 95, 102, 103, 96, 107, 112, 115, 116, 111, 124, 127, 128, 131, 128, 139, 138, 143, 150, 141, 150, 155, 162, 163, 152, 167, 172, 175, 176
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: (1 + 2*x + 5*x^2 + 6*x^3 + 11*x^4 + 12*x^5 + 15*x^6 + 12*x^7 + 19*x^8 + 12*x^9 + 15*x^10 + 12*x^11 + 11*x^12 + 8*x^13 + 5*x^14 + 2*x^15 + x^16 - x^18) / ((1 - x)^2*(1 + x^2)*(1 - x + x^2 - x^3 + x^4)*(1 + x + x^2 + x^3 + x^4)^2).
a(n) = a(n-1) - 2*a(n-2) + 2*a(n-3) - 2*a(n-4) + 3*a(n-5) - 3*a(n-6) + 4*a(n-7) - 4*a(n-8) + 4*a(n-9) - 3*a(n-10) + 3*a(n-11) - 2*a(n-12) + 2*a(n-13) - 2*a(n-14) + a(n-15) - a(n-16) for n>16.
(End)
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PROG
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(PARI) See Links section.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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