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A016200
Expansion of 1/((1-x)(1-2x)(1-6x)).
3
1, 9, 61, 381, 2317, 13965, 83917, 503757, 3023053, 18139341, 108838093, 653032653, 3918204109, 23509241037, 141055478989, 846332939469, 5077997767885, 30467986869453, 182807921741005, 1096847531494605
OFFSET
0,2
FORMULA
a(n) = (9*6^n - 5*2^n + 1)/5. - Bruno Berselli, Feb 09 2011
a(0)=1, a(n) = 6*a(n-1) + 2^(n+1) - 1. - Vincenzo Librandi, Feb 09 2011
a(n) = Sum_{k=0..n} 2^(n-1-k) * (3^(n+1-k) - 1). - J. M. Bergot, Feb 06 2018
MAPLE
seq((9*6^n-5*2^n+1)/5, n=0..100); # Muniru A Asiru, Feb 06 2018
PROG
(GAP) List([0..100], n->(9*6^n-5*2^n+1)/5); # Muniru A Asiru, Feb 06 2018
CROSSREFS
Sequence in context: A005060 A125346 A190666 * A001454 A243877 A200674
KEYWORD
nonn,easy
STATUS
approved