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a(n)=T(n,n-4), T given by A026568. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=4.
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%I #6 Jun 23 2013 12:06:25

%S 1,3,12,34,103,281,778,2072,5524,14488,37918,98474,255137,658351,

%T 1695542,4356520,11177720,28637452,73294698,187412326,478861373,

%U 1222765699,3120722598,7961152560,20302100415,51757554237

%N a(n)=T(n,n-4), T given by A026568. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=4.

%F Conjecture: -2*(n-4)*(n+4)*a(n) +(5*n^2-5*n-46)*a(n-1) +(4*n^2+n+18)*a(n-2) +(-11*n^2+24*n-16)*a(n-3) +2*(n-2)*(2*n-5)*a(n-4)=0. - _R. J. Mathar_, Jun 23 2013

%K nonn

%O 4,2

%A _Clark Kimberling_