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A178935 a(n) = floor((3*4^n - 2*3^n)/5). 3

%I

%S 0,1,6,27,121,517,2166,8955,36697,149413,605526,2445723,9853753,

%T 39627589,159148086,638505531,2559761689,10256265445,41076717846,

%U 164461839579,658312262905,2634643765381,10542759202806,42183589235067,168772014211801,675201028661797

%N a(n) = floor((3*4^n - 2*3^n)/5).

%H Vincenzo Librandi, <a href="/A178935/b178935.txt">Table of n, a(n) for n = 0..1000</a>

%F G.f.: x*(1 - x - 3*x^2 + 4*x^3 - 7*x^4)/(1 - 7*x + 12*x^2 - x^4 + 7*x^5 - 12*x^6) = x*(1 - x - 3*x^2 + 4*x^3 - 7*x^4)/((1-3*x)*(1-4*x)*(1-x^4)).

%F Recurrence: a(n+6) = 7*a(n+5) - 12*a(n+4) + a(n+2) - 7*a(n+1) + 12*a(n).

%o (Maxima) makelist(floor((3*4^n-2*3^n)/5) ,n,0,12);

%o (MAGMA) [Floor((3*4^n-2*3^n)/5): n in [0..30]]; // _Vincenzo Librandi_, Sep 06 2011

%Y Cf. A178934, A178936.

%K nonn,easy

%O 0,3

%A _Emanuele Munarini_, Dec 30 2010

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Last modified January 19 00:03 EST 2021. Contains 340262 sequences. (Running on oeis4.)