k1=ACCT
k2=AGGC
k3=AAAC
k4=AATC

Create the hash table storing the above k-mers using the following hash function

f(A)=1
f(C)=2
f(T)=3
f(G)=4

H(k)= [Sum_i f(k[i])]mod 4 

where k[i] returns the symbol in position i of k


ACCT --> (1+2+2+3)mod 4= 8 mod 4 =0
AGGC --> (1+4+4+2)mod 4= 11 mod 4 =3
AAAC --> (1+1+1+2)mod 4= 5 mod 4=1
AATC --> (1+1+3+2)mod 4= 7 mod 4=3