A348057 Number of n-step self-avoiding walks on three quadrants of a 2D square lattice.

1, 4, 10, 28, 74, 202, 534, 1442, 3822, 10258, 27202, 72718, 192840, 514228, 1363342, 3629316, 9619264, 25575326, 67765590, 180001304, 476807826, 1265567600, 3351529410, 8890447682, 23538665948, 62409037914, 165202281046

Offset

0,2

Links

Table of n, a(n) for n=0..26.

Example

a(2) = 10. Assuming the lower left quadrant is the one removed then a walk of left-down or down-left is not permitted, so the total number of 2-step walks is 4 * 3 - 2 = 10.

Crossrefs

Cf. A001411 (four quadrants), A116903 (two quadrants), A038373 (one quadrant), A129700 (half quadrant).

Sequence in context: A335548 A203293 A111308 * A121302 A026150 A026123

Adjacent sequences: A348054 A348055 A348056 * A348058 A348059 A348060

Keyword

nonn,walk

Author

Scott R. Shannon, Sep 26 2021

Status

approved