Number of (w,x,y,z) with all terms in {0,...,n} and max{w,x,y,z}<=2*min{w,x,y,z}.

Terms

a(0) =1a(1) =2a(2) =17a(3) =32a(4) =97a(5) =162a(6) =337a(7) =512a(8) =881a(9) =1250a(10) =1921a(11) =2592a(12) =3697a(13) =4802a(14) =6497a(15) =8192a(16) =10657a(17) =13122a(18) =16561a(19) =20000a(20) =24641a(21) =29282a(22) =35377a(23) =41472a(24) =49297a(25) =57122a(26) =66977a(27) =76832a(28) =89041a(29) =101250