Number of routes of length 2n on the sides of an octagon from a point to opposite point.

A060995

Number of routes of length 2n on the sides of an octagon from a point to opposite point.

Terms

    a(0) =0a(1) =2a(2) =8a(3) =28a(4) =96a(5) =328a(6) =1120a(7) =3824a(8) =13056a(9) =44576a(10) =152192a(11) =519616a(12) =1774080a(13) =6057088a(14) =20680192a(15) =70606592a(16) =241065984a(17) =823050752a(18) =2810071040a(19) =9594182656a(20) =32756588544a(21) =111837988864a(22) =381838778368

External references