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A115306
a(n) = if n<6 then n else 6*a(floor(n/6)) + 5 - n mod 6.
9
1, 2, 3, 4, 5, 11, 10, 9, 8, 7, 6, 17, 16, 15, 14, 13, 12, 23, 22, 21, 20, 19, 18, 29, 28, 27, 26, 25, 24, 35, 34, 33, 32, 31, 30, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 107
OFFSET
1,2
COMMENTS
Self-inverse permutation of the natural numbers;
if n is written in base 6 representation, then a(n) is the value after replacing all digits d (but not the leading one) by 5-d.
FORMULA
a(n) = A115310(n+4, 5).
MATHEMATICA
a[n_]:=If[n<6, n, 6*a[Floor[n/6]]+5-Mod[n, 6]]; Table[a[n], {n, 72}] (* James C. McMahon, Aug 11 2024 *)
KEYWORD
nonn,base,easy
AUTHOR
Reinhard Zumkeller, Jan 20 2006
STATUS
approved