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%I #18 Sep 08 2022 08:45:41
%S 4,19,79,319,1279,5119,20479,81919,327679,1310719,5242879,20971519,
%T 83886079,335544319,1342177279,5368709119,21474836479,85899345919,
%U 343597383679,1374389534719,5497558138879,21990232555519,87960930222079,351843720888319
%N 5*4^n-1.
%C Second column of the array A132207, or, if this array is flattened, a(n)=A132207(A007583(n)).
%H Vincenzo Librandi, <a href="/A156760/b156760.txt">Table of n, a(n) for n = 0..500</a>
%F a(n) mod 9 = A070403(n+2).
%F a(n+1) = 10*A083420(n)+9 .
%F a(n) = 5*A000302(n)-1.
%F a(n) = ( A024036(n+1)+A140529(n) )/2.
%F a(n) = 4a(n-1)+3, a(0)=4.
%F a(n) = A003947(n+1)-1 = 5*a(n-1)-4*a(n-2). G.f.: (4-x)/((1-x)(1-4x)). - _R. J. Mathar_, Feb 23 2009
%F a(n) = A198693(n) + 2^(2n+1). - _Bob Selcoe_, Apr 20 2015
%e Binary.......................................Decimal
%e 100................................................4
%e 10011.............................................19
%e 1001111...........................................79
%e 100111111........................................319
%e 10011111111.....................................1279
%e 1001111111111...................................5119
%e 100111111111111................................20479
%e 10011111111111111..............................81919
%e 1001111111111111111...........................327679
%e 100111111111111111111........................1310719
%e 10011111111111111111111......................5242879
%e 1001111111111111111111111...................20971519
%e 100111111111111111111111111.................83886079
%e 10011111111111111111111111111..............335544319
%e 1001111111111111111111111111111...........1342177279
%e ... - _Philippe Deléham_, Feb 23 2014
%t Table[5*4^n - 1, {n, 0, 18}] (* _Michael De Vlieger_, Apr 20 2015 *)
%o (Magma) [5*4^n-1: n in [0..30]]; // _Vincenzo Librandi_, Jul 02 2011
%K nonn,easy
%O 0,1
%A _Paul Curtz_, Feb 15 2009
%E Edited and extended by _R. J. Mathar_, Feb 23 2009
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