Sequence1= (all existing 4-digit numbers, no leading zeros);
Sequence2= (each member of seq1 replaced by 1
iff fulfilling both conditions : cond1 and cond2; replaced by 0 otherwise.)
Cond1: k (the number of letters in the English set of words representing N) is even.
For example the number 3024 (three thousand twenty four) does not qualify (23 letters) .
Cond2: the number N is evenly divisible by 3, e.g. the number 3024 qualifies.
Ergo: 3024 of Sequence1 will be replaced by 0 in Sequence2.
Denote by N1 the number of ones in the seq2 and by N0 the number of zeroes in that sequence.
Don't be intimidated by the D4 label,- reread the text carefully and try to answer all of the following questions:
a. What does the RH stand for?
b. Is it true that abs(N1- N0) is an even number?
c. What is the meaning of KISS?
d. Why D4?