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Search: id:A006581
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| A006581 |
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Sum k AND n-k, k = 1 . . n-1.
(Formerly M3225)
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+0
4
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| 1, 0, 4, 4, 5, 0, 12, 16, 21, 16, 24, 20, 17, 0, 32, 48, 65, 64, 84, 84, 85, 64, 92, 96, 101, 80, 88, 68, 49, 0, 80, 128, 177, 192, 244, 260, 277, 256, 316, 336, 357, 336, 360, 340, 321, 256, 336, 368
(list; graph; listen)
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OFFSET
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2,3
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REFERENCES
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Marc LeBrun (mlb(AT)well.com), personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
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G.f.: 1/(1-x)^2 * sum(k>=0, 2^k*t^2/(1+t)^2, t=x^2^k). - R. Stephan, Feb 12 2003
a(0)=a(1)=0, a(2n) = 2a(n-1)+2a(n)+n, a(2n+1) = 4a(n).
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CROSSREFS
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Cf. A090889(n) - A000292(n-2).
Antidiagonal sums of array A003985.
Sequence in context: A111763 A159892 A021696 this_sequence A019922 A092171 A011333
Adjacent sequences: A006578 A006579 A006580 this_sequence A006582 A006583 A006584
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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