A152896 a=b=c=0;c(n)=c+n+a;b(n)=b+n+c;a(n)=a+n+b.

0, 3, 15, 55, 183, 588, 1865, 5887, 18550, 58414, 183904, 578936, 1822459, 5736946, 18059358, 56849069, 178955165, 563332829, 1773314909, 5582216334, 17572253459, 55315679765, 174128175040, 548137914348, 1725482812062

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Dec 14 2008

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (6, -12, 11, -5, 1).

Crossrefs

Cf. A152891, A152895

Programs

Mathematica

lst={};a=b=c=0;Do[c+=n+a;b+=n+c;a+=n+b;AppendTo[lst,a],{n,0,2*4!}];lst
LinearRecurrence[{6,-12,11,-5,1},{0,3,15,55,183},30] (* Harvey P. Dale, Dec 11 2014 *)

Formula

G.f.: x^2(3-3x+x^2)/((1-x)^2*(1-4x+3x^2-x^3)). a(n)=6*a(n-1)-12*a(n-2)+11*a(n-3)-5*a(n-4)+a(n-5). [From R. J. Mathar, Dec 15 2008]