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A160590
Next-to-least significant digit of 2^n.
4
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, 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, 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
OFFSET
4,2
COMMENTS
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).
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...
LINKS
M. Haapanen, What is this and how to prove?, newgsroups sci.math, Mar 28 1996
K. Makella, Mika luku tulee seuraavana?, sfnet.tiede.matematiikka, Jan 2008
Lars Radvall, Multiplar (PDF).
FORMULA
Periodic: a(n+20) = a(n).
MAPLE
for n from 4 to 130 do 2 &^ n mod 100 ; printf("%d, ", floor(%/10)) ; od:
MATHEMATICA
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 *)
CROSSREFS
Sequence in context: A169837 A333010 A319513 * A111952 A068466 A194076
KEYWORD
nonn,base,easy
AUTHOR
Brian Tristam Williams (briantw(AT)briantw.com), May 20 2009
EXTENSIONS
Edited by R. J. Mathar, May 22 2009
STATUS
approved