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Replace 8^k with (-8)^k in base 8 expansion of n.
8

%I #7 Dec 09 2020 01:53:51

%S 0,1,2,3,4,5,6,7,-8,-7,-6,-5,-4,-3,-2,-1,-16,-15,-14,-13,-12,-11,-10,

%T -9,-24,-23,-22,-21,-20,-19,-18,-17,-32,-31,-30,-29,-28,-27,-26,-25,

%U -40,-39,-38,-37,-36,-35,-34,-33,-48,-47,-46,-45,-44,-43,-42,-41,-56,-55,-54,-53,-52,-51,-50,-49

%N Replace 8^k with (-8)^k in base 8 expansion of n.

%C Base 8 representation for n (in lexicographic order) converted from base -8 to base 10.

%H Dana G. Korssjoen, Biyao Li, Stefan Steinerberger, Raghavendra Tripathi, and Ruimin Zhang, <a href="https://arxiv.org/abs/2012.04625">Finding structure in sequences of real numbers via graph theory: a problem list</a>, arXiv:2012.04625, Dec 08, 2020

%F a(8*k+m) = -8*a(k)+m for 0 <= m < 8. - _Chai Wah Wu_, Jan 16 2020

%t f[n_Integer, b_Integer] := Block[{l = IntegerDigits[n]}, Sum[l[[ -i]]*(-b)^(i - 1), {i, 1, Length[l]}]]; a = Table[ FromDigits[ IntegerDigits[n, 8]], {n, 0, 80}]; b = {}; Do[b = Append[b, f[a[[n]], 8]], {n, 1, 80}]; b

%Y Cf. A007094, A073789, A053985, A065369, A073791, A073792, A073793, A073794, A073796 & A073835.

%K base,easy,sign

%O 0,3

%A _Robert G. Wilson v_, Aug 12 2002