

A179579


Number of permutations of 1..n+4 with the number moved left exceeding the number moved right by n or more.


1



37, 73, 142, 276, 539, 1059, 2092, 4150, 8257, 16461, 32858, 65640, 131191, 262279, 524440, 1048746, 2097341, 4194513, 8388838, 16777468, 33554707, 67109163, 134218052, 268435806, 536871289, 1073742229, 2147484082, 4294967760
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OFFSET

1,1


COMMENTS

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


LINKS



FORMULA

Empirical: a(n)=5*a(n1)9*a(n2)+7*a(n3)2*a(n4) ; G.f.: x*(37+112*x110*x^2+36*x^3) / ( (2*x1)*(x1)^3 ).
Empirical: a(n) = (n+4)*(n+1)/2+2^(n+4).  R. J. Mathar, May 26 2016


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



