Composite numbers c satisfying the congruence c * sigma_k(c) == 2 (mod phi(c)) that are "flanked" by 14 at k-1 and k+1.
A392308
Composite numbers c satisfying the congruence c * sigma_k(c) == 2 (mod phi(c)) that are "flanked" by 14 at k-1 and k+1.
Terms
- a(0) =4a(1) =6a(2) =22a(3) =118a(4) =166a(5) =214a(6) =262a(7) =454a(8) =502a(9) =694a(10) =1174a(11) =2038a(12) =2182a(13) =2374a(14) =2566a(15) =2614a(16) =2902a(17) =3046a(18) =3142a(19) =3238a(20) =3622a(21) =3814a(22) =4054a(23) =4918a(24) =5638a(25) =5878a(26) =6406a(27) =6502a(28) =6934a(29) =6982
External references
- oeis: A392308