

A007143


Etrees with exactly 2 colors.
(Formerly M3013)


0



0, 0, 3, 16, 65, 238, 866, 3128, 11493, 42660, 160584, 610640, 2345504, 9081768, 35422175, 139022622, 548671517, 2176051050, 8668363573, 34667284390, 139140830956, 560271494630, 2262709876003, 9163000968554, 37198940600264, 151364381618576
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OFFSET

1,3


REFERENCES

G. Gati, F. Harary and R. W. Robinson, Line colored trees with extendable automorphisms, Acta Math. Scientia, 2 (1982), 105110.
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..26.
G. Gati, F. Harary, R. W. Robinson, Line colored trees with extendable automorphisms, Acta Mathematica Scientia 2.1 (1982), 105110. (Annotated scanned copy)
Index entries for sequences related to trees


FORMULA

a(n) = A007141(n)  2 * A003238(n) for n > 1.  Sean A. Irvine, Oct 30 2017


CROSSREFS

Sequence in context: A267036 A037451 A247363 * A062960 A293579 A044046
Adjacent sequences: A007140 A007141 A007142 * A007144 A007145 A007146


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

a(8) corrected and more terms from Sean A. Irvine, Oct 30 2017


STATUS

approved



