A062257 Number of (0,1)-strings of length n with no occurrences of the substrings 10101101 and 1110101.

1, 2, 4, 8, 16, 32, 64, 127, 251, 496, 981, 1940, 3837, 7590, 15015, 29704, 58763, 116249, 229971, 454942, 899991, 1780410, 3522102, 6967611, 13783703, 27267665, 53942368, 106711708, 211102869, 417615105, 826148769, 1634332138

Offset

0,2

References

I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983, (Example 2.8.11).

Links

Table of n, a(n) for n=0..31.

Formula

G.f.: (1+x^5+x^6+x^7-x^9)/(1+x^5-x^6-x^9-2*x-x^8+x^10). a(n) = 2*a(n-1)-a(n-5)+a(n-6)+a(n-8)+a(n-9)-a(n-10).

Crossrefs

Cf. A062258, A062259.

Sequence in context: A008859 A335247 A145113 * A208127 A172316 A062258

Adjacent sequences: A062254 A062255 A062256 * A062258 A062259 A062260

Keyword

nonn

Author

Vladeta Jovovic, Jun 14 2001

Status

approved