Number of inequivalent ways a semi-infinite curve can cross a straight line n times.

A086441

Number of inequivalent ways a semi-infinite curve can cross a straight line n times.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =27a(6) =79a(7) =213a(8) =644a(9) =1840a(10) =5660

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