Question

Find the first 5 terms of the sequence: an = 4n-1.

Answer 1

#sol1

a1=1×4-1=3
a2=2×4-1=7
a3=3×4-1=11
a4=4×4-1=15
a5=5×5-1=19

#sol2

f(1)=1×4-1=3,
f(n+1)=f(n)+4,
so .... you know.