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A284030 Replacing each term with its digital root generates the original sequence, digit by digit. 1
1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 18, 28, 17, 11, 26, 37, 16, 46, 55, 29, 15, 12, 25, 64, 24, 13, 33, 14, 23, 38, 27, 73, 32, 82, 47, 56, 41, 42, 22, 65, 31, 91, 21, 39, 48, 118, 49, 74, 57, 66, 35, 83, 34, 43, 75, 84, 92, 44, 119, 58, 52, 59, 51, 67, 127, 76, 128, 137, 146, 69, 68, 93, 136, 36, 145, 155, 154, 111, 45, 85, 53, 163, 172, 62, 94, 54, 61, 112, 77, 79, 78, 87, 129, 86, 71, 138, 147 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sequence is started with a(1) = 1 and always extended with the smallest integer not yet present and not leading to a contradiction.

There is no digit "0" in the sequence as "0" cannot be a digital root.

LINKS

Jean-Marc Falcoz, Table of n, a(n) for n = 1..10001

EXAMPLE

After 1,2,3,4,5,6,7,8,9 we have the terms 19,18,28,17,11,26,37,16,46,55,..., whose digital roots are respectively 1,9,1,8,2,8,1,7,1,1,... These digits are precisely the ones used in the sequence, in that order.

CROSSREFS

Cf. A010888 (digital root), A052382 (zeroless numbers).

Sequence in context: A118758 A174025 A106649 * A087121 A087052 A077557

Adjacent sequences: A284027 A284028 A284029 * A284031 A284032 A284033

KEYWORD

base,nonn

AUTHOR

Eric Angelini and Jean-Marc Falcoz, Mar 24 2017

STATUS

approved

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Last modified December 1 03:09 EST 2022. Contains 358454 sequences. (Running on oeis4.)