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Search: id:A006706
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| A006706 |
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Self-convolution of numbers of trees on n nodes. |
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+0
1
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| 1, 2, 3, 4, 7, 12, 23, 44, 90, 186, 407, 902, 2072, 4844, 11595, 28150, 69491, 173522, 438423, 1117968, 2875960, 7453070, 19447591, 51050224, 134749849, 357446716, 952527403, 2548897192, 6846986075, 18458150242, 49923931099, 135443922536
(list; graph; listen)
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OFFSET
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0,2
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LINKS
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Index entries for sequences related to trees
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MAPLE
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with (numtheory): b:= proc(n) option remember; local d, j; if n<=1 then n else (add (add (d*b(d), d= divisors(j)) *b(n-j), j=1..n-1))/ (n-1) fi end: t:= proc(n) option remember; local k; `if` (n=0, 1, b(n)- (add (b(k) *b(n-k), k=1..n-1) -`if` (type (n, odd), 0, b(n/2)))/2) end: a:= n-> add (t(j)* t(n-j), j=0..n): seq (a(n), n=0..40); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 28 2008]
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CROSSREFS
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Cf. A000055.
Sequence in context: A141002 A006537 A103963 this_sequence A124390 A107031 A152605
Adjacent sequences: A006703 A006704 A006705 this_sequence A006707 A006708 A006709
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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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EXTENSIONS
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More terms from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 28 2008
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