A379927 Replacing each term of this sequence S with its digitsum produces a new sequence S' such that S and S' share the same succession of nonzero digits.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 18, 28, 17, 11, 26, 37, 16, 29, 20, 15, 12, 25, 46, 24, 101, 27, 110, 55, 14, 39, 200, 23, 13, 33, 299, 22, 38, 389, 34, 47, 32, 41, 59, 21, 36, 398, 479, 30, 49, 102, 111, 488, 45, 54, 497, 569, 120, 35, 201, 44, 63, 210, 31

Offset

1,2

Comments

The sequence starts with a(1) = 1 and is always extended with the smallest integer not yet present that doesn't lead to a contradiction.

This sequence is a variant of A302656 ignoring zeros; this feature prevents the huge jumps seen in A302656.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, PARI program

Example

The first terms are:
    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 18, 28, 17, 11, 26, 37, 16, 29, 20
The corresponding digitsums are:
    1, 2, 3, 4, 5, 6, 7, 8, 9, 1,  10, 9,  10, 8,  2,  8,  10, 7,  11, 2
Keeping only the nonzero digits we obtain:
    12345678911918281711263716292
and 123456789119182817112.

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A004719, A302656.

Sequence in context: A075905 A321767 A377477 * A207506 A343131 A119246

Adjacent sequences: A379924 A379925 A379926 * A379928 A379929 A379930

Keyword

nonn,base

Author

Rémy Sigrist, Jan 06 2025

Status

approved