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A258592 Values of k such that the number of rooted trees with k nodes (A000081(k)) is even. 3
0, 3, 4, 6, 7, 9, 11, 12, 13, 19, 20, 21, 24, 26, 29, 31, 32, 34, 36, 37, 39, 41, 43, 44, 45, 46, 47, 48, 51, 52, 53, 54, 55, 57, 58, 59, 60, 62, 63, 66, 69, 70, 72, 79, 80, 81, 83, 85, 86, 88, 89, 90, 91, 92, 94, 95, 96, 97, 100, 101, 102, 103, 105, 106, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Complement of A263831.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

MATHEMATICA

Module[{t}, t[1] = 1; t[k_] := t[k] = Sum[DivisorSum[k-m, t[#] # &] t[m]/(k-1), {m, k-1}]; Select[Range[0, 107], EvenQ@t[#] &]] (* after Alois P. Heinz *)

CROSSREFS

Cf. A000081, A211192, A263831.

Sequence in context: A123540 A065313 A103566 * A018825 A247779 A243989

Adjacent sequences:  A258589 A258590 A258591 * A258593 A258594 A258595

KEYWORD

nonn

AUTHOR

Vladimir Reshetnikov, Nov 06 2015

STATUS

approved

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Last modified January 28 00:32 EST 2020. Contains 331313 sequences. (Running on oeis4.)