# riddle of the week

[This article was first published on

Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

**R – Xi'an's Og**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

**T**he Riddler of April 1 offered this simple question:

start with the number 1 and then try to reach a target number through a series of steps. For each step, you can always choose to double the number you currently have. However, if the number happens to be one (1) more than an odd multiple of 3, you can choose to “reduce” — that is, subtract 1 and then divide by 3. What is the smallest positive integer one cannot reach this way?

Which I turned into R steps (while waiting for flight AF19 to Paris)

while((!(x-1)%%3)&((x-1)%%6)){ oor[2*x]TRUE oor[x<-(x-1)%/%3]=TRUE}

but running an exhaustive search till 10⁸ did not spot any missing integer… Maybe an April fool joke (as the quick riddle was asking for the simplest representation of (x-a)(x-b)…(x-z)…!)

To

**leave a comment**for the author, please follow the link and comment on their blog:**R – Xi'an's Og**.R-bloggers.com offers

**daily e-mail updates**about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.

Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.