A007143 - OEIS

A007143

E-trees with exactly 2 colors.
(Formerly M3013)

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

REFERENCES

G. Gati, F. Harary and R. W. Robinson, Line colored trees with extendable automorphisms, Acta Math. Scientia, 2 (1982), 105-110.

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), 105-110. (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: A037451 A398102 A247363 * A359176 A062960 A293579

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