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A198762
3*5^n-1= 2*A057651(n).
1
2, 14, 74, 374, 1874, 9374, 46874, 234374, 1171874, 5859374, 29296874, 146484374, 732421874, 3662109374, 18310546874, 91552734374, 457763671874, 2288818359374, 11444091796874, 57220458984374, 286102294921874, 1430511474609374
OFFSET
0,1
FORMULA
a(n) = 5*a(n-1)+4.
a(n) = 6*a(n-1)-5*a(n-2), n>1.
G.f.: 2*(1 + x)/(1 - 6*x + 5*x^2). - Vincenzo Librandi, Jan 04 2013
MATHEMATICA
CoefficientList[Series[2*(1 + x)/(1 - 6*x + 5*x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 04 2013 *)
LinearRecurrence[{6, -5}, {2, 14}, 30] (* Harvey P. Dale, Mar 19 2013 *)
PROG
(Magma) [(3*5^n-1): n in [0..30]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 30 2011
STATUS
approved