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A262573 Concatenation of the numbers from 1 to n but omitting 3. 0
1, 12, 124, 1245, 12456, 124567, 1245678, 12456789, 1245678910, 124567891011, 12456789101112, 1245678910111213, 124567891011121314, 12456789101112131415, 1245678910111213141516, 124567891011121314151617, 12456789101112131415161718, 1245678910111213141516171819, 124567891011121314151617181920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The only prime among the first 98 terms is a(6) = 124567. Does the sequence contain any other primes?

No other primes through a(10000). - Robert Price, Nov 04 2018

LINKS

Table of n, a(n) for n=1..19.

MATHEMATICA

DeleteDuplicates[Table[FromDigits[Flatten[IntegerDigits[Complement[Range[n], {3}]]]], {n, 20}]] (* Robert Price, Nov 05 2018 *)

Join[{1, 12}, Table[FromDigits[Join[{1, 2}, Flatten[IntegerDigits/@Range[4, n]]]], {n, 4, 20}]] (* Harvey P. Dale, Sep 17 2019 *)

CROSSREFS

Cf. A007908, A262299, A262571-A262582.

See A262300 for more about this problem.

Sequence in context: A125424 A163147 A120918 * A039680 A332690 A016134

Adjacent sequences:  A262570 A262571 A262572 * A262574 A262575 A262576

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Sep 25 2015

STATUS

approved

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Last modified May 5 17:56 EDT 2021. Contains 343572 sequences. (Running on oeis4.)