A115308 - OEIS

%I #6 Mar 30 2012 18:50:53

%S 1,2,3,4,5,6,7,15,14,13,12,11,10,9,8,23,22,21,20,19,18,17,16,31,30,29,

%T 28,27,26,25,24,39,38,37,36,35,34,33,32,47,46,45,44,43,42,41,40,55,54,

%U 53,52,51,50,49,48,63,62,61,60,59,58,57,56,127,126,125,124,123,122,121

%N a(n) = if n<8 then n else 8*a(floor(n/8)) + 7 - n mod 8.

%C Self-inverse permutation of the natural numbers;

%C A115310(n+6,7) = a(n);

%C if n is written in octal representation, then a(n) is the value after replacing all digits d (but not the leading one) by 7-d.

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

%Y Cf. A054429, A115303, A115304, A115305, A115306, A115307, A115309, A106649.

%K nonn,base

%O 1,2

%A _Reinhard Zumkeller_, Jan 20 2006