A048482 a(n) = T(n,n), array T given by A048472.
1, 3, 13, 49, 161, 481, 1345, 3585, 9217, 23041, 56321, 135169, 319489, 745473, 1720321, 3932161, 8912897, 20054017, 44826625, 99614721, 220200961, 484442113, 1061158913, 2315255809, 5033164801, 10905190401, 23555211265, 50734301185, 108984795137
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (7,-18,20,-8).
Programs
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Magma
[(n^2+n)*2^(n-1) + 1: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
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Mathematica
LinearRecurrence[{7,-18,20,-8},{1,3,13,49},30] (* Harvey P. Dale, Feb 02 2015 *) -
PARI
Vec(-(8*x^3-10*x^2+4*x-1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Nov 26 2014
Formula
a(n) = 2 * A001788(n) + 1.
a(n) = (n^2+n)*2^(n-1) + 1. - Ralf Stephan, Sep 02 2003
G.f.: -(8*x^3-10*x^2+4*x-1) / ((x-1)*(2*x-1)^3). - Colin Barker, Nov 26 2014
a(0)=1, a(1)=3, a(2)=13, a(3)=49, a(n)=7*a(n-1)-18*a(n-2)+ 20*a(n-3)- 8*a(n-4). - Harvey P. Dale, Feb 02 2015