Number of first n tetrahedral numbers (A000292) that are relatively prime to n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =2a(5) =2a(6) =4a(7) =2a(8) =6a(9) =1a(10) =8a(11) =2a(12) =10a(13) =2a(14) =5a(15) =4a(16) =14a(17) =3a(18) =16a(19) =2a(20) =7a(21) =4a(22) =20a(23) =4a(24) =10a(25) =5a(26) =18a(27) =4a(28) =26a(29) =2