Duplicate of A081093.A093535Duplicate of A081093.Terms a(0) =3a(1) =7a(2) =31a(3) =127a(4) =3583a(5) =8191a(6) =131071a(7) =524287a(8) =14680063a(9) =1073479679a(10) =2147483647External referencesoeis: A093535