A005979 Number of Hamiltonian rooted triangulations with n internal nodes and 5 external nodes. (Formerly M4000)

5, 45, 420, 4130, 42480, 453350, 4986860, 56251230, 648055650, 7601584050, 90556803600, 1093417607850, 13359234113250, 164935358510470, 2055350730457020, 25827268868350690, 326989527294142480, 4168165020885948440, 53462092704596804720

Offset

0,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

_Peter J. Taylor_, Table of n, a(n) for n = 0..500

P. N. Rathie, The enumeration of Hamiltonian polygons in rooted planar triangulations, Discrete Math., 6 (1973), 163-168.

Formula

a(n) = f(n, 5) where f(n, k) is defined in A003122. - Sean A. Irvine, Feb 02 2015

Prog

(C#) See A003122

Crossrefs

Sequence in context: A173558 A022022 A058410 * A165225 A121272 A346580

Adjacent sequences: A005976 A005977 A005978 * A005980 A005981 A005982

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms and title clarified by Sean A. Irvine, Feb 02 2015

Status

approved