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

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: A267036 A037451 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