A068013 Number of subsets of {1,2,3,...,n} that sum to 0 mod 7.

1, 1, 1, 1, 3, 5, 10, 20, 38, 74, 146, 294, 586, 1172, 2344, 4684, 9364, 18724, 37452, 74900, 149800, 299600, 599192, 1198376, 2396744, 4793496, 9586984, 19173968, 38347936, 76695856, 153391696, 306783376, 613566768, 1227133520, 2454267040