%I A001021 M4869 N2084
%S A001021 1,12,144,1728,20736,248832,2985984,35831808,429981696,5159780352,
%T A001021 61917364224,743008370688,8916100448256,106993205379072,1283918464548864,
%U A001021 15407021574586368,184884258895036416,2218611106740436992
%N A001021 Powers of 12.
%C A001021 Central terms of the triangle in A100851. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Mar 04 2006
%C A001021 Number of n-permutations of 13 objects: n, o, p, q, r, s, t, u, v, w, 
               z, x, y with repetition allowed and containing no u's, (u-free). 
               Permutations with repetitions! If n=0 then 1 >>12^0=1 "". (no u's.) 
               If n=1 then 12 >>12^1=12, >> n, o, p, q, r, s, t, v, w, z, x, y. 
               (no u's.) etc. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Jun 29 2009]
%D A001021 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A001021 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A001021 T. D. Noe, <a href="b001021.txt">Table of n, a(n) for n=0..100</a>
%H A001021 P. J. Cameron, <a href="http://www.cs.uwaterloo.ca/journals/JIS/index.html">
               Sequences realized by oligomorphic permutation groups</a>, J. Integ. 
               Seqs. Vol. 3 (2000), #00.1.5.
%H A001021 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=276">
               Encyclopedia of Combinatorial Structures 276</a>
%H A001021 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%H A001021 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/MasterThesis.pdf">
               Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures</
               a>, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 
               1992.
%H A001021 S. Plouffe, <a href="http://www.lacim.uqam.ca/%7Eplouffe/articles/FonctionsGeneratrices.pdf">
               1031 Generating Functions and Conjectures</a>, Universit\'{e} du 
               Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
%H A001021 Y. Puri and T. Ward, <a href="http://www.cs.uwaterloo.ca/journals/JIS/
               index.html">Arithmetic and growth of periodic orbits</a>, J. Integer 
               Seqs., Vol. 4 (2001), #01.2.1.
%F A001021 G.f.: 1/(1-12x), e.g.f.: exp(12x)
%F A001021 a(n) = 12*a(n-1). [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), 
               Apr 27 2009]
%p A001021 A001021:=-1/(-1+12*z); [S. Plouffe in his 1992 dissertation.]
%o A001021 (Other) sage: [lucas_number1(n,12,0) for n in xrange(1, 19)]# [From Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Apr 27 2009]
%Y A001021 a(n) = A159991(n)/A000351(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               May 02 2009]
%Y A001021 Sequence in context: A163448 A004191 A051051 this_sequence A159490 A000468 
               A076728
%Y A001021 Adjacent sequences: A001018 A001019 A001020 this_sequence A001022 A001023 
               A001024
%K A001021 nonn,easy
%O A001021 0,2
%A A001021 N. J. A. Sloane (njas(AT)research.att.com).