A239086 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.

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

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..68.

Eric Angelini, Less than <, Equal to =, Greater than > (see sequence Se)

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, n-1], k]||Or@@(#<#2==#3&@@@Partition[Flatten[IntegerDigits/@Join[s[[-2;; ]], {k}]], 3, 1]), k++]; k]; Array[a, 68] (* Giorgos Kalogeropoulos, May 14 2022 *)

Crossrefs

The sequences in this family are given in A239083-A239086, A239136-A239139, A239087-A239090, A239215-A239218, A239235.

Sequence in context: A132575 A239235 A031297 * A306866 A187769 A357492

Adjacent sequences: A239083 A239084 A239085 * A239087 A239088 A239089

Keyword

nonn,base

Author

N. J. A. Sloane, Mar 10 2014

Status

approved