login
A016212
Expansion of 1/((1-x)*(1-3*x)*(1-7*x)).
6
1, 11, 90, 670, 4811, 34041, 239380, 1678940, 11762421, 82366471, 576653870, 4036842810, 28258696831, 197813269301, 1384700059560, 9692921940280, 67850518152041, 474953820774531, 3324677326552450, 23272743029259350, 162909206434992051, 1140364460735474161
OFFSET
0,2
FORMULA
a(0)=1, a(1)=11, a(n) = 10*a(n-1) - 21*a(n-2) + 1. - Vincenzo Librandi, Feb 10 2011
a(n) = (7^(n+2) - 3^(n+3) + 2)/24. - Yahia Kahloune, May 06 2013
a(n) = 11*a(n-1) - 31*a(n-2) + 21*a(n-3). - Matthew House, Jan 13 2017
MAPLE
a:=n->sum((7^(n-j)-3^(n-j))/4, j=0..n): seq(a(n), n=1..19); # Zerinvary Lajos, Jan 15 2007
PROG
(PARI) Vec(1/((1-x)*(1-3*x)*(1-7*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
CROSSREFS
Sequence in context: A171470 A168585 A055425 * A037713 A037615 A068973
KEYWORD
nonn,easy
STATUS
approved