A131244 - OEIS

%I #12 Aug 26 2015 00:35:02

%S 1,3,6,14,30,67,146,322,705,1549,3396,7453,16346,35861,78659,172549,

%T 378487,830234,1821136,3994730,8762543,19220904,42161568,92482585,

%U 202863051,444985664,976088107,2141075804,4696507779

%N Row sums of triangle A131243.

%C A131246 is a companion sequence.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,2,-3,-1).

%F G.f. ( 1+x-x^3-2*x^2 ) / ( 1-2*x-2*x^2+3*x^3+x^4 ). - _R. J. Mathar_, Jan 29 2011

%e a(4) = 30 = sum of row 4 terms of A131243: (8 + 7 + 10 + 4 + 1).

%p A065941 := proc(n,k) binomial(n-floor((k+1)/2),floor(k/2)) ; end proc:

%p A131243 := proc(n,k) local a,j ; a := 0 ; for j from k to n do a := a+ A065941(n,j)*A065941(j,k) ; end do: a ; end proc:

%p A131244 := proc(n) add(A131243(n,k),k=0..n) ; end proc:

%p seq(A131244(n),n=0..50) ; # _R. J. Mathar_, Jan 29 2011

%o (PARI) Vec((1+x-x^3-2*x^2)/(1-2*x-2*x^2+3*x^3+x^4)+O(x^99)) \\ _Charles R Greathouse IV_, Jun 12 2015

%Y Cf. A131243, A131245, A131246.

%K nonn,easy

%O 0,2

%A _Gary W. Adamson_, Jun 22 2007