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A049778
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a(n)=Sum{T(n,2k-1): k=1,2,...,[ (n+1)/2 ]}, array T as in A049777.
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2
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1, 3, 9, 17, 32, 50, 78, 110, 155, 205, 271, 343, 434, 532, 652, 780, 933, 1095, 1285, 1485, 1716, 1958, 2234, 2522, 2847, 3185, 3563, 3955, 4390, 4840, 5336, 5848, 6409, 6987, 7617, 8265, 8968, 9690, 10470, 11270, 12131
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (2,1,-4,1,2,-1).
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FORMULA
| G.f.: x*(2x^2+x+1)/[(1-x)^4(1+x)^2]. Pairwise sums of A023855. - R. Stephan, May 06 2004
a(n) = Sum_{k=1..n} k*ceil(k/2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 29 2006
Row sums of triangle A095800^2. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 12 2007
a(n) = 5*n/24+1/16 +3*n^2/8 +n^3/6 -(-1)^n*(1/16 +n/8). - R. J. Mathar, Mar 03 2011
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CROSSREFS
| Cf. A095800.
Sequence in context: A090262 A190815 A006459 * A123325 A116688 A011755
Adjacent sequences: A049775 A049776 A049777 * A049779 A049780 A049781
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KEYWORD
| nonn
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
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