A106649 Replace each digit d (except the leading one) of n with 9-d.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 79, 78, 77

Offset: 0

Author

Zak Seidov, May 12 2005

Keywords

• nonn
• base

Comments

By definition, one-digit numbers do not change.

Differs from A003100 starting with a(21)=29: A003100(21)=20.

Links

• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A003100.

Cf. A054429, A115303, A115304, A115305, A115306, A115307, A115308, A115309.

Programs

Mathematica

a[n_]:=FromDigits[Flatten[{IntegerDigits[n][[1]], Map[9-#&, Drop[IntegerDigits[n], 1]]}]];Table[a[n], {n, 0, 100}]

Formula

a(n) = n if n < 10, otherwise 10*a(floor(n/10)) + 9 - n mod 10; a self-inverse permutation of the natural numbers, A115310(n+8, 9) = a(n) for n > 0. - Reinhard Zumkeller, Jan 20 2006 [corrected by Georg Fischer, Jun 23 2024]

a(n) = A305238(n-9) for 10 <= n <= 99. - M. F. Hasler, Oct 16 2018