Number of strings of numbers x(i=1..7) in 0..n with sum i^2*x(i)^2 equal to n^2*49.

Terms

a(0) =2a(1) =4a(2) =41a(3) =31a(4) =213a(5) =176a(6) =706a(7) =571a(8) =2355a(9) =1508a(10) =5431a(11) =3445a(12) =10802a(13) =6673a(14) =22692a(15) =13525a(16) =39450a(17) =21062a(18) =62786a(19) =39829a(20) =103520a(21) =54727a(22) =160264a(23) =88909a(24) =241185a(25) =123101a(26) =329276a(27) =192191a(28) =488530a(29) =242300