a(n) = A001512(n)/24 = (5*n+1)*(5*n+2)*(5*n+3)*(5*n+4)/24.

Terms

a(0) =1a(1) =126a(2) =1001a(3) =3876a(4) =10626a(5) =23751a(6) =46376a(7) =82251a(8) =135751a(9) =211876a(10) =316251a(11) =455126a(12) =635376a(13) =864501a(14) =1150626a(15) =1502501a(16) =1929501a(17) =2441626a(18) =3049501a(19) =3764376a(20) =4598126a(21) =5563251a(22) =6672876a(23) =7940751a(24) =9381251a(25) =11009376a(26) =12840751a(27) =14891626a(28) =17178876a(29) =19720001