A075617 Rearrangement of natural numbers so that starting with a(n) the concatenation of n numbers gives a composite number.

4, 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 14, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72

Offset

1,1

Links

Table of n, a(n) for n=1..72.

Example

4, 12, 235, 3567, etc. are composite.

Crossrefs

Cf. A075616.

Sequence in context: A072046 A123609 A215645 * A055182 A298919 A190649

Adjacent sequences: A075614 A075615 A075616 * A075618 A075619 A075620

Keyword

base,nonn

Author

Amarnath Murthy, Sep 29 2002

Extensions

Corrected and extended by David Wasserman, Jan 21 2005

Status

approved