A026286 a(n) = greatest k such that s(k) = n, where s = A026284.

6, 8, 10, 12, 14, 17, 20, 23, 26, 29, 31, 34, 36, 39, 41, 44, 46, 49, 51, 54, 57, 59, 62, 65, 67, 70, 73, 75, 78, 81, 83, 86, 89, 91, 94, 96, 99, 102, 104, 107, 109, 112, 115, 117, 120, 122, 125, 128, 130, 133, 135, 138, 141, 143, 146