%I A013726
%S A013726 21,9261,4084101,1801088541,794280046581,350277500542221,
%T A013726 154472377739119461,68122318582951682301,30041942495081691894741,
%U A013726 13248496640331026125580781,5842587018385982521381124421
%N A013726 21^(2n+1).
%H A013726 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A013726 a(n)=441*a(n-1), n>0 ; a(0)=21 . G.f.: 21/(1-441*x). [From Philippe DELEHAM 
               (kolotoko(AT)wanadoo.fr), Nov 28 2008]
%Y A013726 Sequence in context: A074053 A028451 A135823 this_sequence A159358 A048914 
               A046183
%Y A013726 Adjacent sequences: A013723 A013724 A013725 this_sequence A013727 A013728 
               A013729
%K A013726 nonn,easy
%O A013726 0,1
%A A013726 N. J. A. Sloane (njas(AT)research.att.com).