I'm writing an article on Lychrel numbers and some people pointed out that this is completely useless.

My idea is to amend my article with some theories that seemed useless when they are created but found use after some time.

I came with some ideas like the Turing machine but I think I'm not grasping the right examples.

Can someone point me some theories that seemed like the Lychrel numbers and then become 'useful'?

Edit: As some people pointed out that I've published this on MSE I present a code here to find some candidates as Lychrel numbers.

```
def reverseNum(n):
st = str(n)
return int("".join([st[i] for i in xrange(len(st)-1,-1,-1)]))
def isPalindrome (n):
st = str(n)
rev = str(reverseNum(st))
return st==rev
def isLychrel (n, num_interations):
p = n
for i in xrange(num_interations):
if isPalindrome(p):
return i
p = p + reverseNum(p)
return -1
for i in xrange(1000):
p = isLychrel(i,100)
if (p < 0):
print i,p
```

beautiful results, the occurrence ofcomplicated structure, or theuse of unexpected techniquesare also good ways of judging math. $\endgroup$ – André Henriques Dec 17 '12 at 21:39