A147722 Row sums of Riordan array ((1-3x)/(1-4x+x^2), x(1-x)/(1-4x+x^2)).

1, 2, 8, 36, 164, 748, 3412, 15564, 70996, 323852, 1477268, 6738636, 30738644, 140215948, 639602452, 2917580364, 13308696916, 60708323852, 276924225428, 1263204479436, 5762173946324, 26284460772748, 119897955971092, 546920858309964, 2494808379607636, 11380200181418252

Offset: 0

Author

Paul Barry, Nov 11 2008

Keywords

• easy
• nonn

Comments

Row sums of A147721.

Hankel transform of a(n) is [1,4,0,0,0,0,0,0,...]. [Philippe Deléham, Dec 03 2008]

Links

• Indranil Ghosh, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (5,-2).

Programs

Mathematica

CoefficientList[Series[(1 - 3x)/(1 - 5x + 2x^2) , {x, 0, 21}], x] (* Indranil Ghosh, Mar 10 2017 *)
LinearRecurrence[{5,-2},{1,2},30] (* Harvey P. Dale, Aug 26 2021 *)

PARI

Vec((1 - 3*x)/(1 - 5*x + 2*x^2) + O(x^22)) \\ Indranil Ghosh, Mar 10 2017

Formula

G.f.: (1-3x)/(1-5x+2x^2).

a(n) = 5*a(n-1)-2*a(n-2), a(0)=1, a(1)=2. [Philippe Deléham, Nov 13 2008]