Numbers k such that psi(k^2) = k, psi = A002322; indices of 1 in A341857.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =12a(5) =20a(6) =42a(7) =60a(8) =84a(9) =156a(10) =220a(11) =420a(12) =660a(13) =780a(14) =1092a(15) =1806a(16) =1860a(17) =2436a(18) =3612a(19) =3660a(20) =4620a(21) =5060a(22) =5460a(23) =8268a(24) =8580a(25) =12180a(26) =12324a(27) =13020a(28) =15180a(29) =18060