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A303024 Matula-Goebel numbers of anti-binary (no binary branchings) rooted trees. 6
1, 2, 3, 5, 8, 11, 12, 16, 18, 19, 20, 24, 27, 30, 31, 32, 36, 37, 40, 44, 45, 48, 50, 53, 54, 60, 61, 64, 66, 67, 71, 72, 75, 76, 80, 81, 88, 89, 90, 96, 99, 100, 103, 108, 110, 113, 114, 120, 124, 125, 127, 128, 131, 132, 135, 144, 148, 150, 151, 152, 157 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

The sequence of anti-binary rooted trees together with their Matula-Goebel numbers begins:

   1: o

   2: (o)

   3: ((o))

   5: (((o)))

   8: (ooo)

  11: ((((o))))

  12: (oo(o))

  16: (oooo)

  18: (o(o)(o))

  19: ((ooo))

  20: (oo((o)))

  24: (ooo(o))

  27: ((o)(o)(o))

  30: (o(o)((o)))

  31: (((((o)))))

MATHEMATICA

abQ[n_]:=Or[n==1, And[PrimeOmega[n]!=2, And@@Cases[FactorInteger[n], {p_, _}:>abQ[PrimePi[p]]]]]

Select[Range[100], abQ]

CROSSREFS

Cf. A000081, A000598, A001190, A001678, A007097, A061775, A111299, A292050, A298422, A298424.

Cf. A303022, A303023, A303025, A303026, A303027.

Sequence in context: A189716 A002480 A173672 * A070223 A298120 A298205

Adjacent sequences:  A303021 A303022 A303023 * A303025 A303026 A303027

KEYWORD

nonn

AUTHOR

Gus Wiseman, Aug 15 2018

STATUS

approved

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Last modified March 26 12:27 EDT 2019. Contains 321497 sequences. (Running on oeis4.)