A338245 - OEIS

%I #20 Nov 30 2020 10:57:17

%S 0,1,3,4,2,9,10,8,12,13,11,6,7,5,27,28,26,30,31,29,24,25,23,36,37,35,

%T 39,40,38,33,34,32,18,19,17,21,22,20,15,16,14,81,82,80,84,85,83,78,79,

%U 77,90,91,89,93,94,92,87,88,86,72,73,71,75,76,74,69,70,68

%N Nonnegative values in A117966, in order of appearance.

%C This sequence is a permutation of the nonnegative integers with inverse A338247 (the offset has been set to 0 so as to get a permutation).

%C There are only two fixed points: a(0) = 0 and a(1) = 1.

%H Rémy Sigrist, <a href="/A338245/b338245.txt">Table of n, a(n) for n = 0..9841</a>

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

%F a(0) = 0.

%F a(n) = A117966(A132141(n)) for any n > 0.

%e A117966 = 0, 1, -1, 3, 4, 2, -3, -2, -4, 9, 10, 8, 12, 13, 11, 6, 7, 5, ...

%e We keep:  0, 1,     3, 4, 2,             9, 10, 8, 12, 13, 11, 6, 7, 5, ...

%o (PARI) A117966(n) = subst(Pol(apply(x->if(x == 2, -1, x), digits(n, 3)), 'x), 'x, 3)

%o print (select(v -> v>=0, apply(A117966, [0..107])))

%Y See A338248 for a similar sequence.

%Y Cf. A117966, A132141, A338246, A338247.

%K nonn,base

%O 0,3

%A _Rémy Sigrist_, Oct 18 2020