A004309 Hit polynomials, coefficient of y^2 in N_n(y). (Formerly M4720)

0, 10, 60, 595, 4512, 44802, 457040, 5159517, 62939040, 829049884, 11727029860, 177384144795, 2857827179200, 48865616001564, 883930234491000, 16866107046572417, 338568863790331200, 7132984247370166710, 157374949769998613708

Offset

4,2

References

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

Links

Table of n, a(n) for n=4..22.

Earl Glen Whitehead, Jr., Four-discordant permutations, J. Austral. Math. Soc. Ser. A 28 (1979), no. 3, 369-377.

Crossrefs

Sequence in context: A368525 A002493 A054364 * A281863 A219368 A052664

Adjacent sequences: A004306 A004307 A004308 * A004310 A004311 A004312

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Sean A. Irvine, Dec 29 2015

Status

approved