A291890 Number of symmetrically unique Dyck paths of semilength n and height six.

1, 6, 41, 209, 1005, 4411, 18546, 74854, 294293, 1131635, 4280686, 15974526, 58974616, 215772740, 783598381, 2827768273, 10149744903, 36261522803, 129027358151, 457486923079, 1617031493924, 5699720240694, 20040736126691, 70308818376855, 246171461366950

Offset: 6

Author

Alois P. Heinz, Sep 05 2017

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 6..1000
• Index entries for linear recurrences with constant coefficients, signature (12, -51, 66, 144, -540, 411, 510, -1006, 380, 282, -284, 84, -8).

Crossrefs

Column k=6 of A291883.

Formula

G.f.: x^6*(20*x^2-43*x^3+48*x^4-20*x^5+x^7-6*x+1) / ((2*x-1) *(2*x^2-4*x+1) *(x^3-2*x^2-x+1) *(x^3-6*x^2+5*x-1) *(2*x^4-4*x^2+1)).