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A099004
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First differences of A081145.
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9
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1, 2, 3, -4, 5, 6, -9, 7, 8, -14, 10, 11, -18, 12, 13, -24, 15, 16, -30, 17, 19, -34, 20, 21, -39, 22, 23, -43, 25, 26, -50, 27, 28, -54, 29, 31, -57, 33, -32, 35, 36, -70, 37, 38, -73, 40, 41, -78, 42, 44, -85, 45, 46, -90, 47, 48, -94, 49, 51, -97, 52, 53, -104, 55, 56, -109, 58, 59, -116, 61, -60, 62, 63
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listen;
history;
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internal format)
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OFFSET
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1,2
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COMMENTS
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Does every number appear in the sequence of absolute values (see A308007)?
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LINKS
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MATHEMATICA
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f[s_] := Block[{k = 1, d = Abs[Most@s - Rest@s], l = Last@s}, While[MemberQ[s, k] || MemberQ[d, Abs[l - k]], k++ ]; Append[s, k]]; t = Nest[f, {1}, 75]; Rest@t - Most@t (* Robert G. Wilson v, Jun 13 2006 *)
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PROG
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(Python)
A099004_list, l, s, b1, b2 = [1], 2, 3, set(), set([1])
for n in range(2, 5*10**3+1):
....i = s
....while True:
........m = abs(i-l)
........if not (i in b1 or m in b2):
............A099004_list.append(i-l)
............b1.add(i)
............b2.add(m)
............l = i
............while s in b1:
................b1.remove(s)
................s += 1
............break
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 17 2003
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EXTENSIONS
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STATUS
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approved
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