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0, 2, 12, 54, 224, 906, 3636, 14558, 58248, 233010, 932060, 3728262, 14913072, 59652314, 238609284, 954437166, 3817748696, 15270994818, 61083979308, 244335917270, 977343669120, 3909374676522, 15637498706132, 62549994824574
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| In a C/C++ style of notation, the update from a(n-1) to a(n) can be written as a+=(a+=n+a).
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FORMULA
| a(n) = sum_{i=0..n} A020988(i). a(n+1)-a(n)=A020988(n+1).
a(n) = 2*(4^(n+1)-3n-4)/9 = 2*A014825(n). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 21 2008
G.f.: 2*x/((1-x)^2*(1-4*x)). [Colin Barker, Jan 11 2012]
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MATHEMATICA
| lst={}; s=0; Do[s+=(s+=n+s); AppendTo[lst, s], {n, 0, 5!}]; lst
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CROSSREFS
| Cf. A020988.
Sequence in context: A055703 A006738 A111642 * A181765 A198150 A122676
Adjacent sequences: A145763 A145764 A145765 * A145767 A145768 A145769
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KEYWORD
| nonn
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AUTHOR
| Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 18 2008
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EXTENSIONS
| Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 21 2008
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