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A100527 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). 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(a(n))=n: a self-inverse permutation with A001222(a(n))=A001222(n).

LINKS

Table of n, a(n) for n=1..72.

Index entries for sequences that are permutations of the natural numbers

PROG

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)

CROSSREFS

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

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 25 2004

EXTENSIONS

Values through a(72) verified by [From Franklin T. Adams-Watters, Apr 16 2009]

STATUS

approved

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Last modified September 20 16:05 EDT 2017. Contains 292276 sequences.