A300149 Terms from A300148 that disappear, according to the "Erase or triple" protocol (see the Crossref section).

2, 4, 6, 11, 12, 14, 18, 22, 29, 32, 33, 34, 36, 37, 38, 40, 42, 43, 44, 47, 53, 54, 55, 64, 66, 67, 71, 73, 74, 77, 82, 83, 85, 86, 87, 88, 92, 96, 97, 98, 99, 102, 106, 107, 108, 109, 111, 112, 114, 116, 120, 121, 124, 126, 127, 129, 132, 134, 136, 137, 140, 141, 146, 148, 154, 157, 159, 161, 162

Offset

1,1

Comments

The "Erase or triple" protocol describes how to transform an integer K into an integer L: if K has 2 or more identical digits, erase them to get L (1201331 becomes 20); if K has no duplicate digits, triple K to get L (20 becomes 60). Some integers disappear immediately (like 1100 or 9191), other disappear if you apply this protocol to the successive results. This sequence gathers them all.

Note that 1102 is transformed into 2 because no leading zeroes are admitted.

Links

Jean-Marc Falcoz, Table of n, a(n) for n = 1..33333

Example

2 becomes 6 (the triple of 2), then 6 becomes 18 (the triple of 6), then 18 becomes 54 (the triple of 18) and now 162, 486, 1458, 4374, 37 (because the pair 4-4 is erased), 111 (the triple of 37), ... and disappearance.

Crossrefs

Cf. A300148 which shows the first integer (1) entering into a loop.

Sequence in context: A081988 A244748 A245017 * A171921 A030783 A171927

Adjacent sequences: A300146 A300147 A300148 * A300150 A300151 A300152

Keyword

nonn,base

Author

Eric Angelini and Jean-Marc Falcoz, Feb 26 2018

Status

approved