A079966 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}.

1, 0, 1, 0, 2, 1, 4, 2, 7, 5, 14, 12, 27, 26, 53, 57, 106, 122, 212, 258, 428, 543, 868, 1135, 1766, 2364, 3605, 4910, 7374, 10175, 15109, 21054, 30998, 43513, 63656, 89851, 130817, 185416, 268984, 382436, 553308, 788520, 1138525, 1625356, 2343253

Offset: 0

Author

Vladimir Baltic, Feb 19 2003

Keywords

• nonn
• easy

Comments

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

References

• 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.

Links

• Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135.
• Index entries for linear recurrences with constant coefficients, signature (0,1,0,1,1,1).

Crossrefs

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

Formula

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

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