A169722 a(n) = (3*2^(n-1)-1)*(18*2^(n-1)-7).
1, 22, 145, 715, 3151, 13207, 54055, 218695, 879751, 3528967, 14135815, 56583175, 226412551, 905809927, 3623559175, 14494875655, 57980780551, 231925678087, 927707824135, 3710841520135, 14843386527751, 59373587005447, 237494429810695, 949977882820615
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Alice V. Kleeva, Grid for this sequence
- Alice V. Kleeva, Illustration of initial terms
- Robert Munafo, Sequence A169720, and two others by Alice V. Kleeva
- Robert Munafo, Sequence A169720, and two others by Alice V. Kleeva [Cached copy, in pdf format, included with permission]
- Index entries for linear recurrences with constant coefficients, signature (7,-14,8).
Programs
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Magma
I:=[1,22,145]; [n le 3 select I[n] else 7*Self(n-1)-14*Self(n-2)+8*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Dec 04 2012
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Mathematica
LinearRecurrence[{7, -14, 8}, {1, 22, 145}, 30] (* Vincenzo Librandi, Dec 04 2012 *) -
Maxima
makelist(coeff(taylor((1+15*x+5*x^2)/(1-7*x+14*x^2-8*x^3), x, 0, n), x, n), n, 0, 23); /* Bruno Berselli, Dec 04 2012 */
Formula
G.f.: (1+15*x+5*x^2)/(1-7*x+14*x^2-8*x^3). - Bruno Berselli, Dec 04 2012
a(n) = 7*a(n-1)-14*a(n-2)+8*a(n-3). - Vincenzo Librandi, Dec 04 2012