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

Offset

0,5

Links

Table of n, a(n) for n=0..34.

Formula

Empirical G.f.: -(2*x^7+x^5-x^4+x^3+x^2+x-1) / ((2*x-1)*(2*x^7-1)). [Colin Barker, Dec 22 2012]

Crossrefs

7th row of A068009.

Sequence in context: A298184 A182536 A158568 * A342762 A270737 A270724

Adjacent sequences: A068010 A068011 A068012 * A068014 A068015 A068016

Keyword

nonn

Author

Antti Karttunen, Feb 11 2002

Status

approved