Let am=m2k,m∈Z+ and an=n2k,n∈Z+ be two numbers in this sequence.
n2k−m2k=(nk−mk)(nk+mk) If m and n are not consistent numbers the difference n2k−m2k may be either odd or even.
The difference 42k−22k is even.
The difference 42k−32k is odd.
If m and n are not consistent numbers
Suppose n=m+1,m∈Z+
If m is even, then n=m+1 is odd:
{mnis even is odd =>{mknkis even is odd =>
=>{nk−mknk+mkis odd is odd =>(nk−mk)(nk+mk)is odd If m is odd, then n=m+1 is even:
{mnis odd is even =>{mknkis odd is even =>
=>{nk−mknk+mkis odd is odd =>(nk−mk)(nk+mk)is oddTherefore the difference between the consistent numbers in this sequence is odd for all k ∈ N.
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