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A262576 Concatenation of the numbers from 1 to n but omitting 6. 0
1, 12, 123, 1234, 12345, 123457, 1234578, 12345789, 1234578910, 123457891011, 12345789101112, 1234578910111213, 123457891011121314, 12345789101112131415, 1234578910111213141516, 123457891011121314151617, 12345789101112131415161718, 1234578910111213141516171819, 123457891011121314151617181920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The only prime among the first 98 terms is a(6) = 123457. Does the sequence contain any other primes?

No additional primes through the first 2000 terms. - Harvey P. Dale, Sep 27 2018

Differs from A132943 at about the 28th terms.

No primes, other than a(6), through a(10000). - Robert Price, Nov 03 2018

LINKS

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

MATHEMATICA

Module[{nn=20, c}, c=Drop[Range[nn], {6}]; Table[FromDigits[Flatten[ IntegerDigits/@ Take[c, n]]], {n, nn-1}]] (* Harvey P. Dale, Sep 27 2018 *)

CROSSREFS

Cf. A132943.

Cf. A007908, A262299, A262571-A262582.

See A262300 for more about this problem.

Sequence in context: A262578 A262577 A132943 * A262575 A187871 A187869

Adjacent sequences:  A262573 A262574 A262575 * A262577 A262578 A262579

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Sep 25 2015

STATUS

approved

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Last modified May 17 14:58 EDT 2021. Contains 343974 sequences. (Running on oeis4.)