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A100830 Smallest number with same digital root as n but distinct from n and all earlier occurrences. 1
10, 11, 12, 13, 14, 15, 16, 17, 18, 1, 2, 3, 4, 5, 6, 7, 8, 9, 28, 29, 30, 31, 32, 33, 34, 35, 36, 19, 20, 21, 22, 23, 24, 25, 26, 27, 46, 47, 48, 49, 50, 51, 52, 53, 54, 37, 38, 39, 40, 41, 42, 43, 44, 45, 64, 65, 66, 67, 68, 69, 70, 71, 72, 55, 56, 57, 58, 59, 60, 61, 62, 63 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A010888(a(n)) = A010888(n) and a(n)<>n;

a(a(n))=n: self-inverse permutation of the natural numbers.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for sequences that are permutations of the natural numbers

FORMULA

a(n) = n + 9*(-1)^floor((n-1)/9).

PROG

(Haskell)

a100830 n  = n + 9 * (-1) ^ ((n - 1) `div` 9)

-- Reinhard Zumkeller, Aug 01 2014

CROSSREFS

Sequence in context: A262412 A123895 A147519 * A180176 A168100 A088475

Adjacent sequences:  A100827 A100828 A100829 * A100831 A100832 A100833

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Jan 07 2005

STATUS

approved

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Last modified November 20 10:31 EST 2017. Contains 294963 sequences.