



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
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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, sl
....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 !! (n1)
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



