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A190716
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a(2*n) = 2*n and a(2*n-1) = A054569(n).
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2
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1, 2, 7, 4, 21, 6, 43, 8, 73, 10, 111, 12, 157, 14, 211, 16, 273, 18, 343, 20, 421, 22, 507, 24, 601, 26, 703, 28, 813, 30, 931, 32, 1057, 34, 1191, 36, 1333, 38, 1483, 40, 1641, 42, 1807, 44, 1981, 46, 2163, 48, 2353, 50, 2551, 52, 2757, 54, 2971, 56, 3193
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OFFSET
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1,2
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COMMENTS
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Equals the Row2 triangle sums of the Connell sequence A001614 as a triangle. The Row2(n) triangle sums are defined by Row2(n) = sum((-1)^(n+k)*T(n,k), k=1..n), see A180662.
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LINKS
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Table of n, a(n) for n=1..57.
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FORMULA
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a(2*n) = 2*n and a(2*n-1) = 4*n^2 - 6*n + 3
G.f.: x*(1+2*x+4*x^2-2*x^3+3*x^4)/(1-x^2)^3
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MAPLE
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A190716:= n-> coeff (series (x*(1+2*x+4*x^2-2*x^3+3*x^4)/(1-x^2)^3, x, n+1), x, n): seq(A190716(n), n=1..49);
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CROSSREFS
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Sequence in context: A065621 A036565 A054787 * A013623 A210421 A198672
Adjacent sequences: A190713 A190714 A190715 * A190717 A190718 A190719
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KEYWORD
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nonn,easy
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AUTHOR
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Johannes W. Meijer, May 18 2011
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STATUS
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approved
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