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7, 24, 101, 477, 2411, 12729, 69251, 385017, 2175491, 12444489, 71865251, 418096857, 2446626371, 14383667049, 84875140451, 502327573497, 2980183394051, 17715498038409, 105478120962851, 628846706246937, 3753178627502531, 22420395331846569
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) = 1 + (45*2^(2*n+2) + 45*2^(n+2) + 40*3^(n+1) + 5*2^(n+3)*3^(n+1) + 24*5^(n+1))/120.
G.f.: (7 - 123*x + 822*x^2 - 2589*x^3 + 3797*x^4 - 2034*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)).
a(n) = 1 + 3*2^(n-1) + 3*2^(2*n-1) + 3^n + 5^n + 6^n.
a(n) = 21*a(n-1) - 175*a(n-2) + 735*a(n-3) - 1624*a(n-4) + 1764*a(n-5) - 720*a(n-6) for n>5. (End)
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PROG
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(Ruby)
(0..n).map{|i| 1 + (45 * 2 ** (2 * i + 2) + 45 * 2 ** (i + 2) + 40 * 3 ** (i + 1) + 5 * 2 ** (i + 3) * 3 ** (i + 1) + 24 * 5 ** (i + 1)) / 120}
end
(PARI) Vec((7 - 123*x + 822*x^2 - 2589*x^3 + 3797*x^4 - 2034*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)) + O(x^30)) \\ Colin Barker, Mar 08 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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