A262576 Concatenation of the numbers from 1 to n but omitting 6.

1, 12, 123, 1234, 12345, 123457, 1234578, 12345789, 1234578910, 123457891011, 12345789101112, 1234578910111213, 123457891011121314, 12345789101112131415, 1234578910111213141516, 123457891011121314151617, 12345789101112131415161718, 1234578910111213141516171819, 123457891011121314151617181920

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 * A362119 A262575 A187871

Adjacent sequences: A262573 A262574 A262575 * A262577 A262578 A262579

Keyword

nonn,base

Author

N. J. A. Sloane, Sep 25 2015

Status

approved