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A006223
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Number of binary rooted trees of height n requiring 3 registers.
(Formerly M4940)
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1
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1, 14, 118, 780, 4466, 23276, 113620, 528840, 2375100, 10378056, 44381832, 186574864, 773564328, 3171317360, 12880883408, 51915526432, 207893871472, 827983736608
(list; graph; refs; listen; history; internal format)
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OFFSET
| 7,2
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COMMENTS
| Comment from John W. Layman (layman(AT)math.vt.edu): The eighteen listed terms a(7)...a(24) satisfy a(n)=14a(n-1)-78a(n-2)+220a(n-3)-330a(n-4)+252a(n-5)-84a(n-6)+8a(n-7) for n>7 (taking a(1), a(2),..., a(6) = 0). - Oct 14, 1999
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REFERENCES
| Flajolet, P.; Raoult, J.-C.; Vuillemin, J.; The number of registers required for evaluating arithmetic expressions. Theoret. Comput. Sci. 9 (1979), no. 1, 99-125.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
Index entries for sequences related to rooted trees
Index entries for sequences related to trees
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MAPLE
| A006223:=-1/(2*z-1)/(2*z**4-16*z**3+20*z**2-8*z+1)/(2*z**2-4*z+1); [Conjectured (correctly) by S. Plouffe in his 1992 dissertation.]
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CROSSREFS
| Sequence in context: A128569 A138431 A175874 * A091303 A023012 A073383
Adjacent sequences: A006220 A006221 A006222 * A006224 A006225 A006226
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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