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A059155
A hierarchical sequence (S(W'2{3}c) - see A059126).
2
12, 120, 1008, 8160, 65472, 524160, 4194048, 33553920, 268434432, 2147481600, 17179865088, 137438945280, 1099511611392, 8796092989440, 70368744112128, 562949953290240, 4503599627108352, 36028797018439680, 288230376150663168, 2305843009211596800, 18446744073705357312
OFFSET
0,1
FORMULA
G.f.: 12/((8*x-1)*(2*x-1)). [Maksym Voznyy (voznyy(AT)mail.ru), Jul 27 2009]
a(n) = 2^(n+2)*(4^(n+1)-1). - Peter Luschny, May 08 2014
MATHEMATICA
CoefficientList[Series[12/((8 x - 1) (2 x - 1)), {x, 0, 40}], x] (* Vincenzo Librandi, May 09 2014 *)
CROSSREFS
Sequence in context: A067358 A268634 A061506 * A012443 A012274 A009035
KEYWORD
nonn,easy
AUTHOR
Jonas Wallgren, Feb 02 2001
EXTENSIONS
More terms from Peter Luschny, May 08 2014
STATUS
approved