Start with 1 and repeatedly place the first digit at the end of the number and add 6.

1, 7, 13, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37, 79, 103, 37

1,2

After 3 steps the sequence enters a cycle of length 3.

base,nonn

Luc Stevens (lms022(AT)yahoo.com), May 24 2006

approved