A026572 - OEIS

%I #15 May 10 2020 13:43:09

%S 1,2,8,19,56,140,376,953,2474,6286,16097,40880,104069,264052,670414,

%T 1699831,4310546,10924970,27690075,70168812,177820791,450618964,

%U 1142004584,2894347667,7336297080,18597140982,47148420564

%N a(n) = T(n,n-3), T given by A026568. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=3.

%C Also, a(n) = T(n,n-3), T given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=3.

%F Conjectured g.f.: (1/2)*((-3*x^2-x+1)*((x-1)/(4*x^2+x-1))^(1/2)-1+x+x^2)/x^3.  - _Mark van Hoeij_, Oct 30 2011

%F Conjecture: (n+3)*a(n) +(-3*n-5)*a(n-1) +4*(-n-1)*a(n-2) +(13*n-9)*a(n-3) +(5*n-9)*a(n-4) +6*(-2*n+7)*a(n-5)=0. - _R. J. Mathar_, Jun 23 2013

%Y Cf. A026568, A026584.

%K nonn

%O 3,2

%A _Clark Kimberling_