A056238 Nontrivial palindromic denominators in Leibniz's harmonic triangle.
6, 252, 272, 858, 2772, 4004, 6006, 289982, 2370732, 2629262, 6039306, 27999972, 28233282, 2704884072, 20278187202, 20591819502, 2592587852952, 2936231326392, 21809166190812, 27237788773272, 229145919541922
Offset: 1
Crossrefs
Cf. A007622.