Numbers k such that phi(k) = phi(2*k-1) where phi is the Euler totient function (A000010).

Terms

a(0) =1a(1) =1313a(2) =1853a(3) =6683a(4) =12773a(5) =28823a(6) =194123a(7) =198743a(8) =343493a(9) =702923a(10) =829793a(11) =1309853a(12) =1379963a(13) =1846763a(14) =2001203a(15) =2788913a(16) =3911603a(17) =5399363a(18) =5464463a(19) =5689373a(20) =10728113a(21) =11316143a(22) =11776853a(23) =12082073a(24) =14588213a(25) =16587383a(26) =19610063a(27) =20294243a(28) =21470963a(29) =25388963