

A006967


Number of graceful permutations of length n.
(Formerly M3229)


10



1, 1, 2, 4, 4, 8, 24, 32, 40, 120, 296, 648, 1328, 3200, 9912, 25592, 55920, 143192, 510696, 1451296, 3497344, 10451824, 38570704, 118914992, 315235872, 1014824752, 3963684496, 13166130152, 37846301904, 130507967088, 533318630936, 1884550215976, 5800121391936
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OFFSET

0,3


COMMENTS

Also the number of graceful labelings of the path graph P_n.  Eric W. Weisstein, Mar 31 2020


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
H. S. Wilf and N. Yoshimura, Ranking rooted trees and a graceful application, in Discrete Algorithms and Complexity (Proceedings of the JapanUS joint seminar, 1986, Kyoto, Japan), edited by D. Johnson, T. Nishizeki, A. Nozaki and H. S. Wilf, Academic Press, NY, 1987, pp. 341350.


LINKS



FORMULA



PROG

(CWEB) programs by Don Knuth: see links above


CROSSREFS



KEYWORD

nonn,nice,hard


AUTHOR



EXTENSIONS

n=2 term corrected June 1996
More terms from Michal Adamaszek (aszek(AT)mimuw.edu.pl), Aug 22 2006
a(41)=1032009647743958000 from Don Knuth, Sep 10 2020


STATUS

approved



