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A007152 Evolutionary trees of magnitude n.
(Formerly M3628)
2
1, 1, 4, 28, 301, 4466, 84974, 1974904, 54233540, 1718280152, 61695193880, 2475688513024, 109797950475448, 5333253012414224, 281576039542538368, 16055279332196218624, 983264280857581866112, 64369946360185677026048, 4485859513184032011682304, 331558482325457407154881024 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

L. R. Foulds and R. W. Robinson, Counting certain classes of evolutionary trees with singleton labels, Congress. Num., 44 (1984), 65-88.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..20.

L. R. Foulds and R. W. Robinson, Counting certain classes of evolutionary trees with singleton labels, Congress. Num., 44 (1984), 65-88. (Annotated scanned copy)

Index entries for sequences related to trees

MAPLE

Q  := proc(n)

    option remember ;

    if n <= 1 then

        0;

    else

        A007151(n)-A007151(n-1) +(n-1)*procname(n-1) ; # eq (3.5)

        %/2 ;

    end if;

end proc:

A007152 := proc(n)

    if n = 1 then

        1;

    else

        A007151(n-1)+Q(n-1) ; # eq (3.9)

    end if ;

end proc:

seq(A007152(n), n=1..20 ); # R. J. Mathar, Mar 19 2018

CROSSREFS

Cf. A007151.

Sequence in context: A112938 A307083 A274043 * A295258 A177554 A316212

Adjacent sequences:  A007149 A007150 A007151 * A007153 A007154 A007155

KEYWORD

nonn,easy

AUTHOR

Robert W. Robinson

STATUS

approved

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Last modified December 15 00:30 EST 2019. Contains 329988 sequences. (Running on oeis4.)