A362093 a(1) = 1, a(2) = 2; for n > 2, a(n) is the least positive integer not occurring earlier such that a(n) shares no digit with a(n-1) - a(n-2).

1, 2, 3, 4, 5, 6, 7, 8, 9, 20, 22, 10, 30, 11, 23, 33, 24, 12, 34, 13, 35, 14, 36, 15, 37, 16, 38, 17, 39, 18, 40, 19, 43, 31, 44, 25, 26, 27, 28, 29, 32, 21, 42, 45, 41, 50, 46, 51, 47, 52, 48, 53, 49, 55, 54, 56, 57, 58, 59, 60, 62, 61, 63, 64, 65, 66, 67, 68, 69, 70, 72, 71, 73, 74, 75, 76, 77

Offset

1,2

Comments

The sequence is likely to be finite although it contains at least 1 million terms.

Sequence is finite with 6080472 terms, since a(6080471) = 660606060 and a(6080472) = 8822811 have difference -651783249. - Michael S. Branicky, Apr 09 2023

Links

Table of n, a(n) for n=1..77.

Michael S. Branicky, Python program

Scott R. Shannon, Image of the first 1 million terms. The green line is a(n) = n.

Example

a(11) = 22 as a(10) - a(9) = 20 - 9 = 11, and 22 is the smallest unused number that does not contain the digit 1.

Prog

(Python) # see link for program that generates full sequence

Crossrefs

Cf. A362075, A362076, A342441, A342442, A067581, A297065.

Sequence in context: A140281 A039077 A247803 * A052383 A110803 A109795

Adjacent sequences: A362090 A362091 A362092 * A362094 A362095 A362096

Keyword

nonn

Author

Scott R. Shannon, Apr 08 2023

Status

approved