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

0, 1, 6, 27, 121, 517, 2166, 8955, 36697, 149413, 605526, 2445723, 9853753, 39627589, 159148086, 638505531, 2559761689, 10256265445, 41076717846, 164461839579, 658312262905, 2634643765381, 10542759202806, 42183589235067, 168772014211801, 675201028661797

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Formula

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)).

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

Prog

(Maxima) makelist(floor((3*4^n-2*3^n)/5) , n, 0, 12);
(Magma) [Floor((3*4^n-2*3^n)/5): n in [0..30]]; // Vincenzo Librandi, Sep 06 2011

Crossrefs

Cf. A178934, A178936.

Sequence in context: A080627 A079762 A175716 * A249792 A002912 A030297

Adjacent sequences: A178932 A178933 A178934 * A178936 A178937 A178938

Keyword

nonn,easy

Author

Emanuele Munarini, Dec 30 2010

Status

approved