A048507 a(n) = T(2,n), array T given by A048505.
1, 10, 35, 101, 269, 685, 1693, 4093, 9725, 22781, 52733, 120829, 274429, 618493, 1384445, 3080189, 6815741, 15007741, 32899069, 71827453, 156237821, 338690045, 731906045, 1577058301, 3388997629, 7264534525, 15535702013, 33151778813, 70598524925
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..2000
- Index entries for linear recurrences with constant coefficients, signature (7,-18,20,-8).
Programs
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Magma
[(n^2+9*n+16) * 2^(n-2) - 3: n in [0..30]]; // Vincenzo Librandi, Sep 26 2011
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Mathematica
LinearRecurrence[{7,-18,20,-8},{1,10,35,101},30] (* Harvey P. Dale, Jan 21 2021 *) -
PARI
Vec((16*x^3-17*x^2+3*x+1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ Colin Barker, Nov 27 2014
Formula
a(n) = (n^2+9*n+16) * 2^(n-2) - 3. - Ralf Stephan, Feb 05 2004
a(n) = 7*a(n-1)-18*a(n-2)+20*a(n-3)-8*a(n-4). - Colin Barker, Nov 27 2014
G.f.: (16*x^3-17*x^2+3*x+1) / ((x-1)*(2*x-1)^3). - Colin Barker, Nov 27 2014
Comments