a(n) = 462*n^6 + 330*n^4 - 165*n^3 + 55*n^2 - 11*n + 1.

Terms

a(0) =1a(1) =672a(2) =33727a(3) =359536a(4) =1967109a(5) =7405696a(6) =21949027a(7) =55092192a(8) =122381161a(9) =247574944a(10) =465140391a(11) =823079632a(12) =1386090157a(13) =2239057536a(14) =3490880779a(15) =5278630336a(16) =7772038737a(17) =11178323872a(18) =15747344911a(19) =21777090864a(20) =29619501781a(21) =39686622592a(22) =52457089587