A079966 - OEIS

%I #17 Apr 16 2024 04:17:21

%S 1,0,1,0,2,1,4,2,7,5,14,12,27,26,53,57,106,122,212,258,428,543,868,

%T 1135,1766,2364,3605,4910,7374,10175,15109,21054,30998,43513,63656,

%U 89851,130817,185416,268984,382436,553308,788520,1138525,1625356,2343253

%N Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,2}.

%C Number of compositions (ordered partitions) of n into elements of the set {2,4,5,6}.

%D D. H. Lehmer, Permutations with strongly restricted displacements. Combinatorial theory and its applications, II (Proc. Colloq., Balatonfured, 1969), pp. 755-770. North-Holland, Amsterdam, 1970.

%H Vladimir Baltic, <a href="http://pefmath.etf.rs/vol4num1/AADM-Vol4-No1-119-135.pdf">On the number of certain types of strongly restricted permutations</a>, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135.

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,0,1,1,1).

%F a(n) = a(n-2)+a(n-4)+a(n-5)+a(n-6).

%F G.f.: -1/(x^6+x^5+x^4+x^2-1).

%Y Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.

%K nonn,easy

%O 0,5

%A _Vladimir Baltic_, Feb 19 2003