I know I am cheating :-)

A) $a_n = n + C \lfloor \frac{n}{N}\rfloor$

B) Integers of form $x+\prod_{1 \leq k \leq N}{(x-k)}$

I know I am cheating :-)

A) $a_n = n + C \lfloor \frac{n}{N}\rfloor$

B) Integers of form $x+\prod_{1 \leq k \leq N}{(x-k)}$

EDIT: up to $N$ A and B coincide with $\mathbb{N}$ so it is a triple in a sense.