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 A067422 Seventh column of triangle A067417. 3
 1, 9, 189, 3969, 83349, 1750329, 36756909, 771895089, 16209796869, 340405734249, 7148520419229, 150118928803809, 3152497504879989, 66202447602479769, 1390251399652075149, 29195279392693578129 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..700 FORMULA a(n) = A067417(n+6, 6). a(n) = 9*(3*7)^(n-1), n >= 1, a(0)=1. G.f.: (1-12*x)/(1-21*x). PROG (MAGMA) [Ceiling(9*(3*7)^(n-1)): n in [0..20]]; // Vincenzo Librandi, Oct 02 2011 CROSSREFS Cf. A067421 (sixth column), A067423 (eighth column), A009965 (powers of 21). Sequence in context: A196682 A124008 A033713 * A249932 A278751 A145240 Adjacent sequences:  A067419 A067420 A067421 * A067423 A067424 A067425 KEYWORD nonn,easy AUTHOR Wolfdieter Lang, Jan 25 2002 STATUS approved

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Last modified February 18 02:15 EST 2019. Contains 320237 sequences. (Running on oeis4.)