The OEIS is supported by the many generous donors to the OEIS Foundation.


(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A141836 a(n) = first term that can be reduced in n steps via repeated interpretation of a(n) as a base b+1 number where b is the largest digit of a(n), such that b is always 2 so that each interpretation is base 3. Terms already fully reduced (i.e., single digits) are excluded. 6
12, 202, 21111, 1001221220, 2120202222022022102 (list; graph; refs; listen; history; text; internal format)
It is possible to compute additional terms by taking the last term, treating it as base-10 and converting to base-3. This will necessarily create a term which can converted back to base 10 yielding the previous term in the sequence which will itself yield N further terms. But there is no guarantee (except in base 2) that the term so derived will be the first term to produce a sequence of N+1 terms. There could be another, smaller, term which satisfies that requirement but which uses different terms. Pushing the last term of this sequence yields 2120202222022022102 as a possible next term.
a(3) = 21111 because 21111 is the first number that can produce a sequence of three terms by repeated interpretation as a base 3 number: [21111] (base-3) --> [202] (base-3) --> [20] (base-3) --> [6]. Since 6 cannot be interpreted as a base 3 number, the sequence terminates with 20. a(1) = 12 because 12 is the first number that can be reduced once, yielding no further terms interpretable as base 3.
Sequence in context: A277311 A327073 A133242 * A363382 A083932 A080316
Chuck Seggelin (seqfan(AT)plastereddragon.com), Jul 10 2008
a(5) from Giovanni Resta, Feb 23 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 1 16:12 EST 2024. Contains 370442 sequences. (Running on oeis4.)