Task 1: Esthetic Number

You are given a positive integer, $n.

Write a script to find out if the given number is Esthetic Number.

An esthetic number is a positive integer where every adjacent digit
differs from its neighbour by +-1.

For example,

5456 is an esthetic number as |5 - 4| = |4 - 5| = |5 - 6| = 1
120 is not an esthetic numner as |2 - 0| != 1

MY NOTES: ok, sounds quite easy.  Let's make it slightly harder by allowing
ourselves (in debug mode) to reproduce the examples as written.. although
note that I've cheated slighltly: I've simplified the "not" output format
above to show only the first "|a-b| != 1", because it's not quite clear
what the output should be in all cases.

GUEST LANGUAGE: As a bonus, I also had a go at translating ch-1.pl
into C (look in the C directory for that).


Task 2: Sylvester's sequence

Write a script to generate first 10 members of Sylvester's sequence. For
more informations, please refer to the wikipedia page:
  https://en.wikipedia.org/wiki/Sylvester%27s_sequence

(In summary, each term of the sequence is the product of the previous
terms, plus one. The first few terms of the sequence are 2, 3, 7, 43, 1807)

Output

2
3
7
43
1807
3263443
10650056950807
113423713055421844361000443
12864938683278671740537145998360961546653259485195807
165506647324519964198468195444439180017513152706377497841851388766535868639572406808911988131737645185443

MY NOTES: Also very easy, although the numbers grow ridiculously fast.
Sounds like a job for BigInt.