Semiprimes p*q such that 2^(p+q) == 1 (mod p*q).

Terms

a(0) =9a(1) =15a(2) =35a(3) =119a(4) =5543a(5) =74447a(6) =90859a(7) =110767a(8) =222179a(9) =389993a(10) =1526849a(11) =2927297a(12) =3626699a(13) =4559939a(14) =24017531a(15) =137051711a(16) =160832099a(17) =229731743a(18) =627699239a(19) =880021141a(20) =1001124539a(21) =1041287603a(22) =1104903617a(23) =1592658611a(24) =1717999139a(25) =8843679683a(26) =15575602979a(27) =15614760199a(28) =20374337479