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*(-146+776*x-1620*x^2+1677*x^3-868*x^4+180*x^5) / ( (2*x-1)^2*(x-1)^4 ).
Empirical: a(n) = (n+5)*2^(n+4) + (n+5)*(n^2-5*n-42)/6. - R. J. Mathar, May 26 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, g.f. from R. J. Mathar in the Sequence Fans Mailing List, Jul 19 2010
STATUS
approved