A079964 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={0,4}.

1, 0, 1, 1, 2, 2, 5, 5, 10, 13, 22, 30, 50, 70, 112, 163, 254, 375, 579, 862, 1320, 1979, 3015, 4536, 6893, 10392, 15764, 23800, 36064, 54492, 82521, 124748, 188841, 285561, 432174, 653642, 989097, 1496125, 2263754, 3424425, 5181150, 7837946

Offset: 0

Author

Vladimir Baltic, Feb 19 2003

Keywords

• nonn
• easy

Comments

Number of compositions (ordered partitions) of n into elements of the set {2,3,4,6}.

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 (0,1,1,1,0,1).

Crossrefs

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

Formula

a(n) = a(n-2)+a(n-3)+a(n-4)+a(n-6).

G.f.: -1/(x^6+x^4+x^3+x^2-1).