Numbers k such that k^2 divides 15^k-1.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =8a(5) =14a(6) =16a(7) =28a(8) =56a(9) =112a(10) =136a(11) =272a(12) =452a(13) =812a(14) =904a(15) =952a(16) =1624a(17) =1808a(18) =1904a(19) =3164a(20) =3248a(21) =6328a(22) =11912a(23) =12656a(24) =15368a(25) =18632a(26) =23824a(27) =27608a(28) =30736a(29) =37264