A026271 a(n) = sum of the numbers between the two n's in A026242.
0, 3, 6, 14, 25, 33, 49, 60, 81, 105, 121, 150, 182, 203, 240, 264, 306, 351, 380, 430, 462, 517, 575, 612, 675, 741, 783, 854, 899, 975, 1054, 1104, 1188, 1275, 1330, 1422, 1480, 1577, 1677, 1740, 1845, 1911, 2021, 2134, 2205
Offset: 1