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 A000237 Number of mixed Husimi trees with n nodes; or rooted polygonal cacti with bridges. (Formerly M2754 N1107) 12
 0, 1, 1, 3, 8, 26, 84, 297, 1066, 3976, 15093, 58426, 229189, 910127, 3649165, 14756491, 60103220, 246357081, 1015406251, 4205873378, 17497745509, 73084575666, 306352303774, 1288328048865, 5433980577776, 22982025183983 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Christian G. Bower, Table of n, a(n) for n=0..500 C. G. Bower, Transforms (2) G. W. Ford and G. E. Uhlenbeck, Combinatorial problems in the theory of graphs III, Proc. Nat. Acad. Sci. USA, 42 (1956), 529-535. N. J. A. Sloane, Transforms FORMULA Shifts left under transform T where Ta = EULER(BIK(a)). [See Transforms links.] - Christian G. Bower, Nov 15 1998 PROG (PARI) BIK(p)={(1/(1-p) + (1+p)/subst(1-p, x, x^2))/2} EulerT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, 1/n))))-1, -#v)} seq(n)={my(v=[0]); for(n=1, n, v=concat([0, 1], EulerT(Vec(BIK(Ser(v))-1)))); v} \\ Andrew Howroyd, Aug 30 2018 CROSSREFS Cf. A000083, A000314, A035082, A035349-A035357. Sequence in context: A148803 A148804 A148805 * A148806 A148807 A148808 Adjacent sequences:  A000234 A000235 A000236 * A000238 A000239 A000240 KEYWORD nonn,eigen,nice,easy AUTHOR EXTENSIONS More terms from Christian G. Bower, Nov 15 1998 STATUS approved

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Last modified May 30 08:04 EDT 2020. Contains 334712 sequences. (Running on oeis4.)