Number of strings of numbers x(i=1..n) in 0..6 with sum i*x(i) equal to n*6.

Terms

a(0) =1a(1) =4a(2) =17a(3) =74a(4) =282a(5) =985a(6) =3142a(7) =9353a(8) =26146a(9) =69331a(10) =175410a(11) =426006a(12) =997336a(13) =2259816a(14) =4971190a(15) =10646876a(16) =22251915a(17) =45477519a(18) =91049794a(19) =178855119a(20) =345194427a(21) =655396606a(22) =1225461491a(23) =2258813924a(24) =4108018840a(25) =7377439511a(26) =13092332036