A026247 a(n) = (1/2)*s(n), where s(n) is n-th even number in A002251.
1, 5, 2, 3, 9, 10, 4, 13, 14, 6, 17, 18, 7, 8, 22, 26, 27, 11, 30, 31, 12, 34, 35, 39, 15, 16, 43, 47, 48, 19, 51, 52, 20, 21, 56, 60, 23, 24, 64, 65, 25, 68, 69, 73, 28, 29, 77, 81, 82, 32, 85, 86, 33, 89, 90, 94, 36, 37, 98, 99, 38, 102, 103
Offset: 1