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A119641 Prime numbers of trees with n unlabeled nodes. 2
2, 3, 11, 23, 47, 1301, 7741, 83453838443384019701, 3497830604170469202903845457503189, 3043448204076362393100321053325760617159315927820231750001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A000055(n) is semiprime for n = 6, 10, 11, 12, 17, 23, 32, 41, 56, 72, no more through 100. - Jonathan Vos Post, Feb 08 2011

LINKS

Table of n, a(n) for n=1..10.

FORMULA

A000040 INTERSECTION A000055.

a(n) = A000055(A119642(n)). - Amiram Eldar, Apr 22 2018

CROSSREFS

Cf. A000055, A119642.

Sequence in context: A141123 A263729 A246496 * A252005 A074496 A292817

Adjacent sequences:  A119638 A119639 A119640 * A119642 A119643 A119644

KEYWORD

nonn

AUTHOR

Jorge Coveiro, Jul 27 2006

EXTENSIONS

Offset changed by Michel Marcus, Apr 23 2018

STATUS

approved

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Last modified May 26 17:17 EDT 2019. Contains 323597 sequences. (Running on oeis4.)