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A199214
a(n) = 3*5^n+1.
1
4, 16, 76, 376, 1876, 9376, 46876, 234376, 1171876, 5859376, 29296876, 146484376, 732421876, 3662109376, 18310546876, 91552734376, 457763671876, 2288818359376, 11444091796876, 57220458984376, 286102294921876, 1430511474609376
OFFSET
0,1
FORMULA
a(n) = 4*A083065(n).
a(n) = 5*a(n-1)-4.
a(n) = 6*a(n-1)-5*a(n-2).
G.f.: 4*(1-2*x)/((1-x)*(1-5*x)). - Bruno Berselli, Nov 04 2011
MATHEMATICA
LinearRecurrence[{6, -5}, {4, 16}, 30] (* Harvey P. Dale, Jul 08 2013 *)
PROG
(Magma) [3*5^n+1: n in [0..30]];
CROSSREFS
Cf. A083065.
Sequence in context: A050540 A346662 A094559 * A374566 A241023 A200725
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 04 2011
STATUS
approved