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Self-inverse permutation of natural numbers: a(1) = 1, a(2) = 2, a(A055938(n)) = A005187(a(n)), a(A005187(n)) = A055938(a(n)).
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%I #8 Dec 14 2016 23:39:29

%S 1,2,5,12,3,8,27,6,22,17,58,4,15,50,13,45,10,36,121,41,32,9,30,112,

%T 103,28,7,26,97,23,92,21,86,75,248,18,70,84,65,237,20,61,79,63,16,227,

%U 210,56,59,14,221,201,55,196,53,48,187,11,49,191,42,180,44,175,39,154,503,168,146,37,141,491,171,132,34,137,165,478,43,128

%N Self-inverse permutation of natural numbers: a(1) = 1, a(2) = 2, a(A055938(n)) = A005187(a(n)), a(A005187(n)) = A055938(a(n)).

%H Antti Karttunen, <a href="/A279347/b279347.txt">Table of n, a(n) for n = 1..8192</a>

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

%F a(1) = 1, a(2) = 2, for n > 2, A079559(n) = 0 [when n is a term of A055938], a(n) = A005187(a(A256992(n))), otherwise a(n) = A055938(a(A256992(n))).

%F As a composition of other permutations:

%F a(n) = A279342(A279343(n)).

%F a(n) = A279344(A279341(n)).

%e a(1) = 1 and a(2) = 2 by definition.

%e Because A005187(2) = 3, a(3) = A055938(a(2)) = 5, and vice versa, as A055938(2) = 5, a(5) = A005187(a(2)) = 3.

%e Because A005187(3) = 4, a(4) = A055938(a(3)) = A055938(5) = 12.

%e Because A055938(3) = 6, a(6) = A005187(a(3)) = A005187(5) = 8.

%o (Scheme) (definec (A279347 n) (cond ((<= n 2) n) ((zero? (A079559 n)) (A005187 (A279347 (A256992 n)))) (else (A055938 (A279347 (A256992 n))))))

%Y Cf. A005187, A055938, A079559, A256992.

%Y Related or similar permutations: A279341, A279342, A279343, A279344.

%K nonn

%O 1,2

%A _Antti Karttunen_, Dec 10 2016