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1, 6, 15, 28, 46, 69, 96, 127, 163, 204, 249, 298, 352, 411, 474, 541, 613, 690, 771, 856, 946, 1041, 1140, 1243, 1351, 1464, 1581, 1702, 1828, 1959, 2094, 2233, 2377, 2526, 2679, 2836, 2998, 3165, 3336, 3511, 3691, 3876, 4065, 4258, 4456, 4659
(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 + 3*x + x^2 + 3*x^3 + x^4)/((1 - x)^3*(1 + x^2)).
a(n) = 3*a(n-1) - 4*a(n-2) + 4*a(n-3) - 3*a(n-4) + a(n-5) for n > 4.
(End)
a(n) = (5 + 9*n*(1 + n) - A087960(n))/4.
E.g.f.: (exp(x)*(5 + 18*x + 9*x^2) - cos(x) + sin(x))/4. (End)
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PROG
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(PARI) Vec((1 + 3*x + x^2 + 3*x^3 + x^4) / ((1 - x)^3*(1 + x^2)) + O(x^60)) \\ Colin Barker, Mar 23 2018
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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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