A274083 Number of unrooted labeled trees on 4n+2 nodes with node degree either one or five.

1, 6, 3150, 12612600, 192972780000, 8046096548490000, 747480957758835300000, 135330984231708815550000000, 43401712634861734607093640000000, 22953694145310867501311470722000000000, 18935469872719334117190133449041218500000000

Offset

0,2

Comments

There are no unrooted labeled trees on 4n or 4n+1 or 4n+3 nodes with node degree either one or five.

Links

Table of n, a(n) for n=0..10.

Math.Stackexchange.com, Marko Riedel et al., Number of labeled trees

Maple

seq(binomial(4*n+2, n)*(4*n)!/4!^n, n=0..20);

Mathematica

Table[Binomial[4*n+2, n]*(4*n)!/(4!)^n, {n, 0, 10}] (* G. C. Greubel, Jun 09 2016 *)

Crossrefs

Cf. A274056, A000272, A274081.

Sequence in context: A114184 A093884 A265869 * A079183 A030245 A247965

Adjacent sequences: A274080 A274081 A274082 * A274084 A274085 A274086

Keyword

nonn

Author

Marko Riedel, Jun 09 2016

Status

approved