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A082746
For n odd, a(n) is the least positive integer not already used. For n even, a(n) is the least positive integer not already used that is coprime to a(n/2).
3
1, 2, 3, 5, 4, 7, 6, 8, 9, 11, 10, 12, 13, 17, 14, 15, 16, 19, 18, 20, 21, 23, 22, 25, 24, 27, 26, 28, 29, 31, 30, 32, 33, 35, 34, 36, 37, 41, 38, 39, 40, 43, 42, 44, 45, 47, 46, 48, 49, 53, 50, 52, 51, 55, 54, 57, 56, 59, 58, 60, 61, 67, 62, 63, 64, 65, 66, 68, 69, 71, 70, 73
OFFSET
1,2
COMMENTS
a(4) = 5 is coprime to a(8) = 8. - David Wasserman, Sep 28 2004
LINKS
PROG
(PARI) used = vector(100); A = vector(80); least = 1; for (i = 1, 40, while (used[least], least = least + 1); A[i + i - 1] = least; used[least] = 1; m = least + 1; while (used[m] || gcd(m, A[i]) > 1, m = m + 1); A[i + i] = m; used[m] = 1); A
CROSSREFS
Sequence in context: A340401 A160051 A351298 * A098313 A098311 A342265
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 16 2003
EXTENSIONS
More terms from David Wasserman, Sep 28 2004
STATUS
approved