OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..400
Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (April, 2010), 119-135.
Index entries for linear recurrences with constant coefficients, signature (1,2,3,5,6,-1,-1,0,-1,-1).
FORMULA
Recurrence: a(n) = a(n-1)+2*a(n-2)+3*a(n-3)+5*a(n-4)+6*a(n-5)-a(n-6)-a(n-7)-a(n-9)-a(n-10).
G.f.: (1-x^5-x^3-x^2)/(x^10+x^9+x^7+x^6-6*x^5-5*x^4-3*x^3-2*x^2-x+1). [Corrected by Georg Fischer, May 15 2019]
MATHEMATICA
LinearRecurrence[{1, 2, 3, 5, 6, -1, -1, 0, -1, -1}, {1, 2, 6, 18, 46, 115, 301, 792, 2068, 5380}, 30] (* Harvey P. Dale, Aug 15 2014 *)
PROG
(PARI) a(n)=([0, 1, 0, 0, 0, 0, 0, 0, 0, 0; 0, 0, 1, 0, 0, 0, 0, 0, 0, 0; 0, 0, 0, 1, 0, 0, 0, 0, 0, 0; 0, 0, 0, 0, 1, 0, 0, 0, 0, 0; 0, 0, 0, 0, 0, 1, 0, 0, 0, 0; 0, 0, 0, 0, 0, 0, 1, 0, 0, 0; 0, 0, 0, 0, 0, 0, 0, 1, 0, 0; 0, 0, 0, 0, 0, 0, 0, 0, 1, 0; 0, 0, 0, 0, 0, 0, 0, 0, 0, 1; -1, -1, 0, -1, -1, 6, 5, 3, 2, 1]^(n-1)*[1; 2; 6; 18; 46; 115; 301; 792; 2068; 5380])[1, 1] \\ Charles R Greathouse IV, Jul 28 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Baltic, Jul 21 2002
STATUS
approved