A026059 a(n) = (d(n)-r(n))/5, where d = A026057 and r is the periodic sequence with fundamental period (1,0,3,1,0).
5, 10, 16, 25, 36, 49, 65, 83, 105, 130, 158, 190, 225, 265, 309, 357, 410, 467, 530, 598, 671, 750, 834, 925, 1022, 1125, 1235, 1351, 1475, 1606, 1744, 1890, 2043, 2205, 2375, 2553, 2740, 2935, 3140, 3354, 3577, 3810, 4052, 4305, 4568, 4841, 5125, 5419, 5725, 6042, 6370, 6710, 7061, 7425, 7801, 8189, 8590
Offset: 4