A032611 Concatenation of n and n + 6 or {n,n+6}.
17, 28, 39, 410, 511, 612, 713, 814, 915, 1016, 1117, 1218, 1319, 1420, 1521, 1622, 1723, 1824, 1925, 2026, 2127, 2228, 2329, 2430, 2531, 2632, 2733, 2834, 2935, 3036, 3137, 3238, 3339, 3440, 3541, 3642, 3743, 3844, 3945, 4046, 4147, 4248
Offset: 1