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A121202
a(n) = 12*n + 7^n - 5^n.
1
0, 14, 48, 254, 1824, 13742, 102096, 745502, 5374272, 38400590, 272709744, 1928498750, 13597146720, 95668307438, 672119557392, 4717043931998, 33080342679168, 231867574534286, 1624598900645040, 11379821699045246
OFFSET
0,2
FORMULA
G.f.: 2*(7*x-74*x^2+211*x^3)/((1-x)^2*(1-5*x)*(1-7*x)). - Vincenzo Librandi, Feb 25 2013
a(n) = 14*a(n-1)-60*a(n-2)+82*a(n-3)-35*a(n-4). - Vincenzo Librandi, Feb 27 2013
MATHEMATICA
CoefficientList[Series[2 (7 x - 74 x^2 + 211 x^3)/((1-x)^2 (1-5 x)(1-7 x)), {x, 0, 30}], x] (* Vincenzo Librandi, Feb 25 2013 *)
PROG
(Magma) [7^n - 5^n + 12*n: n in [0..30]]; // Vincenzo Librandi, Feb 25 2013
(Magma) I:=[0, 14, 48, 254]; [n le 4 select I[n] else 14*Self(n-1)-60*Self(n-2)+82*Self(n-3)-35*Self(n-4): n in [1..20]]; // Vincenzo Librandi, Feb 25 2013
CROSSREFS
Cf. A074616.
Sequence in context: A195966 A337421 A345724 * A345691 A251228 A250973
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Aug 19 2006
EXTENSIONS
Edited by Ray Chandler, Sep 06 2006
STATUS
approved