

A239215


The sequence S = a(1), a(2), ... is defined by a(1)=1, if d,e,f are consecutive digits then we do not have d >= e > f, and S is always extended with the smallest integer not yet present in S.


18



1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22, 23, 24, 25, 26, 27, 28, 29, 33, 34, 35, 36, 37, 38, 39, 44, 45, 46, 47, 48, 49, 55, 56, 57, 58, 59, 66, 67, 68, 69, 77, 78, 79, 88, 89, 99, 999, 9999, 99999, 999999, 9999999, 99999999
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OFFSET

1,2


COMMENTS

Computed by Lars Blomberg.


REFERENCES

Eric Angelini, Posting to Sequence Fans Mailing List, Sep 28 2013


LINKS

Table of n, a(n) for n=1..60.
Eric Angelini, Less than <, Equal to =, Greater than > (see sequence Sr)
Eric Angelini, Less than <, Equal to =, Greater than > [Cached copy, with permission of the author]


MATHEMATICA

a[1]=1; a[n_]:=a[n]=Block[{k=1}, While[MemberQ[s=Array[a, n1], k]Or@@(#>=#2>#3&@@@Partition[Flatten[IntegerDigits/@Join[Last@s, {k}]], 3, 1]), k++]; k]; Array[a, 56] (* Giorgos Kalogeropoulos, May 13 2022 *)


CROSSREFS

The sequences in this family are given in A239083A239086, A239136A239139, A239087A239090, A239215A239218, A239235.
Sequence in context: A239016 A102827 A190221 * A055571 A132781 A318275
Adjacent sequences: A239212 A239213 A239214 * A239216 A239217 A239218


KEYWORD

nonn,base


AUTHOR

Michel Marcus, Mar 12 2014


STATUS

approved



