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A306216 Successive concatenation of the current sequence with the first differences of the sequence, a(1) = a(2) = 1.

%I A306216 #15 Feb 01 2019 01:33:09
%S A306216 1,1,0,0,-1,0,-1,0,-1,0,-1,0,-1,1,-1,1,-1,0,-1,0,-1,1,-1,1,-1,1,-1,1,
%T A306216 -1,2,-2,2,-2,0,-1,0,-1,1,-1,1,-1,1,-1,1,-1,2,-2,2,-2,1,-1,1,-1,2,-2,
%U A306216 2,-2,2,-2,2,-2,3,-4,4,-4,0,-1,0,-1,1,-1,1,-1,1,-1
%N A306216 Successive concatenation of the current sequence with the first differences of the sequence, a(1) = a(2) = 1.
%C A306216 n | generation             | first differences
%C A306216 --+------------------------+-------------------
%C A306216 1 | [1,1]                  | [0]
%C A306216 2 | [1,1,0]                | [0,-1]
%C A306216 3 | [1,1,0,0,-1]           | [0,-1,0,-1]
%C A306216 4 | [1,1,0,0,-1,0,-1,0,-1] | [0,-1,0,-1,1,-1,1,-1]
%H A306216 Peter Kagey, <a href="/A306216/b306216.txt">Table of n, a(n) for n = 1..8193</a> (first 14 generations)
%t A306216 Nest[Join[#, Differences@ #] &, {1, 1}, 7] (* _Michael De Vlieger_, Jan 29 2019 *)
%o A306216 (Ruby)
%o A306216 generations = 10
%o A306216 (1...generations).reduce([1,1]) do |s, _|
%o A306216   s += s.each_cons(2).map { |a, b| b - a }
%o A306216 end
%o A306216 (Haskell)
%o A306216 a306216_list = 1 : 1 : concat (Data.List.unfoldr nextGeneration [1,1]) where
%o A306216   nextGeneration l = Just (diff l, l ++ diff l)
%o A306216   diff xs =  zipWith subtract xs (tail xs)
%Y A306216 Cf. A107946, A306211.
%K A306216 sign,look
%O A306216 1,30
%A A306216 _Peter Kagey_, Jan 29 2019