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 A059138 A hierarchical sequence (S(W3{2,2}cc) - see A059126). 0
 18, 90, 270, 666, 1494, 3186, 6606, 13482, 27270, 54882, 110142, 220698, 441846, 884178, 1768878 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS J. Wallgren, Hierarchical sequences FORMULA Conjectures from Colin Barker, Oct 07 2015: (Start) a(n) = 18*(-5+3*2^(1+n)-2*n) = 18*A050488(n+1). a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3) for n>2. G.f.: -18*(x+1) / ((x-1)^2*(2*x-1)). (End) CROSSREFS Sequence in context: A063788 A066854 A247901 * A117735 A041624 A227812 Adjacent sequences:  A059135 A059136 A059137 * A059139 A059140 A059141 KEYWORD easy,nonn,more AUTHOR Jonas Wallgren, Jan 19 2001 STATUS approved

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Last modified January 23 23:56 EST 2021. Contains 340398 sequences. (Running on oeis4.)