195814

Appears in sequences

• Consider a string of n 1. From left to right for any couple of consecutive numbers apply the transform 11 -> 10, 10 -> 11, 00 -> 00, 01 -> 01. At any further step restart the process considering the value of the rightmost digit as input to the leftmost one to apply the transform again. Sequence gives the number of steps necessary to reach again a string of n 1 or -1 if such a number does not exist.at n=17A281922
• a(n) = the smallest positive integer that produces a product that contains the digit 2 when multiplied by 2 at most n times, and where a further multiplication by 2 produces a number that does not contain the digit 2. Set a(n) = -1 if no such number exists.at n=33A381183