A262574 Concatenation of the numbers from 1 to n but omitting 4.

1, 12, 123, 1235, 12356, 123567, 1235678, 12356789, 1235678910, 123567891011, 12356789101112, 1235678910111213, 123567891011121314, 12356789101112131415, 1235678910111213141516, 123567891011121314151617, 12356789101112131415161718, 1235678910111213141516171819, 123567891011121314151617181920

Offset

1,2

Comments

The only prime among the first 98 terms is a(8) = 12356789. Does the sequence contain any other primes?

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

Links

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

Mathematica

DeleteDuplicates[Table[FromDigits[Flatten[IntegerDigits[Complement[Range[n], {4}]]]], {n, 20}]] (* Robert Price, Nov 05 2018 *)

Crossrefs

Cf. A007908, A262299, A262571-A262582.

See A262300 for more about this problem.

Sequence in context: A187871 A187869 A362117 * A159901 A159900 A134802

Adjacent sequences: A262571 A262572 A262573 * A262575 A262576 A262577

Keyword

nonn,base

Author

N. J. A. Sloane, Sep 25 2015

Status

approved