A179580 Number of permutations of 1..n+5 with the number moved left exceeding the number moved right by n or more

219, 534, 1236, 2774, 6109, 13290, 28670, 61466, 131135, 278638, 589992, 1245422, 2621761, 5505442, 11534866, 24117906, 50332451, 104858566, 218104956, 452986182, 939525669, 1946158874, 4026533926, 8321501514, 17179871879

Offset

1,1

Comments

Recurrence would also extend to an a(0) if the definition were made to exclude the identity permutation

Links

R. H. Hardin, Table of n, a(n) for n=1..99

Formula

Empirical: a(n)=8*a(n-1)-26*a(n-2)+44*a(n-3)-41*a(n-4)+20*a(n-5)-4*a(n-6) ; G.f.: -x*(-219+1218*x-2658*x^2+2866*x^3-1536*x^4+328*x^5) / ( (2*x-1)^2*(x-1)^4 ).

Empirical: a(n) = (n+5)*(n^2-2*n-36)/6 +(n+7)*2^(n+4). - R. J. Mathar, May 26 2016

Crossrefs

Sequence in context: A361343 A192086 A256815 * A043435 A166836 A200827

Adjacent sequences: A179577 A179578 A179579 * A179581 A179582 A179583

Keyword

nonn

Author

R. H. Hardin, g.f. from R. J. Mathar in the Sequence Fans Mailing List, Jul 19 2010

Status

approved