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 A175499 a(n) = A175498(n+1)-A175498(n). 7
 1, 2, -1, 3, 4, -5, 6, -4, 5, -3, 7, -8, 9, -2, 8, -10, 11, -6, 10, -14, 12, -7, 13, -12, 14, -13, 15, -11, 16, -19, 17, -9, 18, -21, 19, -17, 20, -18, 21, -15, 22, -26, 23, -16, 24, -29, 25, -22, 27, -23, 26, -25, 28, -27, 29, -28, 30, -24, 31, -35, 32, 33, -62, 34, -31, 35, -34, 36, -33, 37, -39, 38, -32, 39, -42, 40, -36 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS No integer occurs in this sequence more than once, by definition. Is this sequence a permutation of the nonzero integers? LINKS Chai Wah Wu, Table of n, a(n) for n = 1..4999 MATHEMATICA a[1] = 0; d[1] = 1; k = 1; z = 10000; zz = 120; A[k_] := Table[a[i], {i, 1, k}]; diff[k_] := Table[d[i], {i, 1, k}]; c[k_] := Complement[Range[-z, z], diff[k]]; T[k_] := -a[k] + Complement[Range[z], A[k]] Table[{h = Min[Intersection[c[k], T[k]]], a[k + 1] = a[k] + h,    d[k + 1] = h, k = k + 1}, {i, 1, zz}]; u = Table[a[k], {k, 1, zz}]  (* A257884 *) Table[d[k], {k, 1, zz}] (* A175499 *) (* Clark Kimberling, May 13 2015 *) PROG (Python) A175499_list, l, s, b = [1], 2, 3, set() for n in range(2, 10**2): ....i, j = s, s-l ....while True: ........if not (i in b or j in A175499_list): ............A175499_list.append(j) ............b.add(i) ............l = i ............while s in b: ................b.remove(s) ................s += 1 ............break ........i += 1 ........j += 1 # Chai Wah Wu, Dec 15 2014 (Haskell) a175499 n = a175499_list !! (n-1) a175499_list = zipWith (-) (tail a175498_list) a175498_list -- Reinhard Zumkeller, Apr 25 2015 CROSSREFS Cf. A175498, A257884, A131389. Sequence in context: A169808 A283069 A304528 * A181440 A035043 A288118 Adjacent sequences:  A175496 A175497 A175498 * A175500 A175501 A175502 KEYWORD sign AUTHOR Leroy Quet, May 31 2010 EXTENSIONS More terms from Sean A. Irvine, Jan 27 2011 STATUS approved

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Last modified December 10 20:55 EST 2018. Contains 318049 sequences. (Running on oeis4.)