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Permutation of natural numbers: a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).
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%I #9 Dec 13 2023 08:23:02

%S 1,2,3,4,5,6,9,8,10,12,7,18,15,16,20,24,25,14,21,36,30,32,27,40,48,50,

%T 28,42,33,72,11,60,64,54,80,96,51,100,56,84,35,66,45,144,22,120,57,

%U 128,108,160,192,102,69,200,112,168,70,132,49,90,39,288,44,240,114,256,55,216,320,384,105,204,87,138,400

%N Permutation of natural numbers: a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).

%H Antti Karttunen, <a href="/A269857/b269857.txt">Table of n, a(n) for n = 1..2662</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%F a(1) = 1; if n is an odd prime, a(n) = A250469(a(A026233(n))), else a(n) = 2*(a(A026233(n))).

%F As a composition of other permutations:

%F a(n) = A252755(A071574(n)).

%o (Scheme, with memoization-macro definec)

%o (definec (A269857 n) (cond ((<= n 1) n) ((and (odd? n) (= 1 (A010051 n))) (A250469 (A269857 (A026233 n)))) (else (A005843 (A269857 (A026233 n))))))

%Y Inverse: A269858.

%Y Cf. A005843, A026233, A010051, A250469.

%Y Related or similar permutations: A071574, A252755, A269847.

%Y Differs from A269847 for the first time at n=19, where a(19)=21, while A269847(19)=27.

%K nonn

%O 1,2

%A _Antti Karttunen_, Mar 06 2016