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Number of subsets of {1,2,3,...,n} that sum to 0 mod 10.
2

%I #7 Mar 06 2016 16:25:00

%S 1,1,1,1,2,4,7,13,26,52,104,206,410,820,1640,3280,6556,13108,26216,

%T 52432,104864,209720,419432,838864,1677728,3355456,6710896,13421776,

%U 26843552,53687104,107374208,214748384,429496736,858993472,1717986944

%N Number of subsets of {1,2,3,...,n} that sum to 0 mod 10.

%F Empirical G.f.: (x-1)*(2*x^7+3*x^6+4*x^5+2*x^4+2*x^3+x^2-1) / ((2*x-1)*(2*x^5-1)). [_Colin Barker_, Dec 22 2012]

%Y 10th row of A068009.

%K nonn

%O 0,5

%A _Antti Karttunen_, Feb 11 2002