A115307 a(n) = if n<7 then n else 7*a(floor(n/7)) + 6 - n mod 7.

1, 2, 3, 4, 5, 6, 13, 12, 11, 10, 9, 8, 7, 20, 19, 18, 17, 16, 15, 14, 27, 26, 25, 24, 23, 22, 21, 34, 33, 32, 31, 30, 29, 28, 41, 40, 39, 38, 37, 36, 35, 48, 47, 46, 45, 44, 43, 42, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74

Offset

1,2

Comments

Self-inverse permutation of the natural numbers;

A115310(n+5,6) = a(n);

if n is written in base 7 representation, then a(n) is the value after replacing all digits d (but not the leading one) by 6-d.

Links

Table of n, a(n) for n=1..72.

Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A054429, A115303, A115304, A115305, A115306, A115308, A115309, A106649.

Sequence in context: A165304 A266642 A245450 * A171597 A086185 A072564

Adjacent sequences: A115304 A115305 A115306 * A115308 A115309 A115310

Keyword

nonn,base

Author

Reinhard Zumkeller, Jan 20 2006

Status

approved