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A190571 Number of n-step one-sided prudent walks, avoiding exactly three consecutive west steps and three consecutive east steps. 0
1, 3, 7, 15, 37, 85, 199, 467, 1089, 2549, 5959, 13931, 32577, 76165, 178087, 416395, 973585, 2276389, 5322519, 12444811, 29097761, 68034725, 159074951, 371940043, 869649137, 2033364389, 4754297463, 11116229131, 25991337537, 60771473701 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

S. Gao, H. Niederhausen, Sequences Arising From Prudent Self-Avoiding Walks (submitted to INTEGERS: The Electronic Journal of Combinatorial Number Theory).

LINKS

Table of n, a(n) for n=1..30.

FORMULA

G.f.: x*(1+x-2*x^3+2*x^4)/(1-2*x-x^2+2*x^4-2*x^5).

CROSSREFS

Sequence in context: A223167 A183557 A255962 * A317881 A018020 A192472

Adjacent sequences:  A190568 A190569 A190570 * A190572 A190573 A190574

KEYWORD

nonn,walk

AUTHOR

Shanzhen Gao, May 12 2011

STATUS

approved

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Last modified November 17 18:24 EST 2019. Contains 329241 sequences. (Running on oeis4.)