a(n) is the number of paths to reach a position outside an 8 X 8 chessboard after n steps, starting in one of the corners, when performing a walk with unit steps on the square lattice.

A376837

a(n) is the number of paths to reach a position outside an 8 X 8 chessboard after n steps, starting in one of the corners, when performing a walk with unit steps on the square lattice.

Terms

    a(0) =2a(1) =2a(2) =6a(3) =12a(4) =40a(5) =100a(6) =350a(7) =982a(8) =3542a(9) =10738a(10) =39556a(11) =127272a(12) =475332a(13) =1602458a(14) =6030830a(15) =21056830a(16) =79514918a(17) =284645860a(18) =1075801928a(19) =3917238476a(20) =14799350958a(21) =54498514998a(22) =205721183302a(23) =763140403282

External references