A075610 a(1) = 1, a(n) = smallest prime number not occurring earlier such that the concatenation a(n-1) and a(n) is a composite number.

1, 2, 5, 7, 11, 13, 3, 19, 17, 29, 23, 31, 41, 37, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 97, 89, 103, 101, 109, 107, 113, 127, 131, 137, 139, 149, 151, 167, 157, 173, 163, 179, 181, 191, 193, 197, 199, 223, 227, 211, 233, 229, 239, 241, 251, 269, 263, 271, 257, 277

Offset

1,2

Links

Table of n, a(n) for n=1..60.

Crossrefs

Cf. A075607, A075608, A075609.

Sequence in context: A030498 A355774 A079933 * A057922 A243047 A113543

Adjacent sequences: A075607 A075608 A075609 * A075611 A075612 A075613

Keyword

base,nonn

Author

Amarnath Murthy, Sep 28 2002

Extensions

More terms from Michel ten Voorde Jun 23 2003

Status

approved