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A100527
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a(1) = 1, n>1: a(n) = smallest m<>n and not occurring earlier such that m has as many prime-factors as n has (with repetition).
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2
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1, 3, 2, 6, 7, 4, 5, 12, 10, 9, 13, 8, 11, 15, 14, 24, 19, 20, 17, 18, 22, 21, 29, 16, 26, 25, 28, 27, 23, 42, 37, 48, 34, 33, 38, 40, 31, 35, 46, 36, 43, 30, 41, 45, 44, 39, 53, 32, 51, 52, 49, 50, 47, 56, 57, 54, 55, 62, 61, 81, 59, 58, 66, 96, 69, 63, 71, 70, 65, 68, 67, 80
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OFFSET
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1,2
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COMMENTS
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a(a(n))=n: a self-inverse permutation with A001222(a(n))=A001222(n).
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LINKS
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Table of n, a(n) for n=1..72.
Index entries for sequences that are permutations of the natural numbers
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PROG
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Contribution from Franklin T. Adams-Watters, Apr 16 2009: (Start)
(PARI) invect(v, n, x)=for(i=1, n, if(v[i]==x, return(1))); 0
nextnew(v, n)=local(k); k=1; while(!R(n, k)||invect(v, n-1, k), k++); k
newvect(n)=local(v); v=vector(n); for(k=1, n, v[k]=nextnew(v, k)); v
R(n, m)=bigomega(n)==bigomega(m)&&n!=m||n==1&&m==1
newvect(80) (End)
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CROSSREFS
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Cf. A094681, A159588. [From Franklin T. Adams-Watters, Apr 16 2009]
Sequence in context: A267100 A178754 A276446 * A276445 A063946 A154441
Adjacent sequences: A100524 A100525 A100526 * A100528 A100529 A100530
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, Nov 25 2004
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EXTENSIONS
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Values through a(72) verified by [From Franklin T. Adams-Watters, Apr 16 2009]
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STATUS
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approved
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