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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 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) 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 STATUS approved

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