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A160590 Next-to-least significant digit of 2^n.

%I A160590 #16 Oct 22 2023 16:08:11
%S A160590 1,3,6,2,5,1,2,4,9,9,8,6,3,7,4,8,7,5,0,0,1,3,6,2,5,1,2,4,9,9,8,6,3,7,
%T A160590 4,8,7,5,0,0,1,3,6,2,5,1,2,4,9,9,8,6,3,7,4,8,7,5,0,0,1,3,6,2,5,1,2,4,
%U A160590 9,9,8,6,3,7,4,8,7,5,0,0,1,3,6,2,5,1,2,4,9,9,8,6,3,7,4,8,7,5,0,0,1,3,6,2,5
%N A160590 Next-to-least significant digit of 2^n.
%C A160590 In the sequence [1, 2, 4, 8,] 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, (A000079) the least-significant digit recurs as [..], 6,2,4,8.. (A000689).
%C A160590 The second-least-significant digit repeats in the sequence [..],1,3,6,2,5,1,2,4,9,9,8,6,3,7,4,8,7,5,0,0...
%H A160590 Paolo Xausa, <a href="/A160590/b160590.txt">Table of n, a(n) for n = 4..10000</a>
%H A160590 M. Haapanen, <a href="http://groups.google.com/group/sci.math/tree/browse_frm/month/1996-3/43b7a3e7153ce92e?rnum=1141&amp;start=1000&amp;_done=%2Fgroup%2Fsci.math%2Fbrowse_frm%2Fmonth%2F1996-3%3Fstart%3D1000%26sa%3DN%26#doc_2bf6437ac1907bdc">What is this and how to prove?</a>, newgsroups sci.math, Mar 28 1996
%H A160590 K. Makella, <a href="http://sfnet.fi/group.php?newsgroup=sfnet.tiede.matematiikka&amp;sid=&amp;id=4709&amp;headers=2">Mika luku tulee seuraavana?</a>, sfnet.tiede.matematiikka, Jan 2008
%H A160590 Lars Radvall, <a href="http://hem.passagen.se/larsvall/matte/multiplar/multiplar.pdf">Multiplar (PDF)</a>.
%H A160590 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,-1,1).
%F A160590 Periodic: a(n+20) = a(n).
%p A160590 for n from 4 to 130 do 2 &^ n mod 100 ; printf("%d,", floor(%/10)) ; od:
%t A160590 PadRight[{},100,{1,3,6,2,5,1,2,4,9,9,8,6,3,7,4,8,7,5,0,0}] (* _Paolo Xausa_, Oct 22 2023 *)
%Y A160590 Cf. A000079, A000689.
%K A160590 nonn,base,easy
%O A160590 4,2
%A A160590 Brian Tristam Williams (briantw(AT)briantw.com), May 20 2009
%E A160590 Edited by _R. J. Mathar_, May 22 2009