A115305 a(n) = if n<5 then n else 5*a(floor(n/5)) + 4 - n mod 5.

1, 2, 3, 4, 9, 8, 7, 6, 5, 14, 13, 12, 11, 10, 19, 18, 17, 16, 15, 24, 23, 22, 21, 20, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52

Offset

1,2

Comments

Self-inverse permutation of the natural numbers;

A115310(n+3,4) = a(n);

if n is written in base 5 representation, then a(n) is the value after replacing all digits d (but not the leading one) by 4-d.

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Index entries for sequences that are permutations of the natural numbers

Mathematica

Table[d = IntegerDigits[n, 5]; FromDigits[Prepend[4 - Rest@d, d[[1]]], 5], {n, 72}] (* Ivan Neretin, Apr 26 2017 *)

Crossrefs

Cf. A054429, A115303, A115304, A115306, A115307, A115308, A115309, A106649.

Sequence in context: A249543 A307404 A307405 * A210747 A353239 A351497

Adjacent sequences: A115302 A115303 A115304 * A115306 A115307 A115308

Keyword

nonn,base

Author

Reinhard Zumkeller, Jan 20 2006

Status

approved