Number of ordered quadruples (a,b,c,d) with gcd(a,b,c,d)=1 (1 <= {a,b,c,d} <= n).

Terms

a(0) =1a(1) =15a(2) =79a(3) =239a(4) =607a(5) =1199a(6) =2303a(7) =3823a(8) =6223a(9) =9279a(10) =13919a(11) =19183a(12) =27007a(13) =35743a(14) =47519a(15) =60735a(16) =78719a(17) =97103a(18) =122447a(19) =148527a(20) =181839a(21) =216959a(22) =262543a(23) =306863a(24) =365343a(25) =423855a(26) =495855a(27) =569055a(28) =661679a(29) =748527