General pattern for a sequence

Question

I have this sequence: $1,2,5,6,9,10,13,14,17,18,\ldots$

I would like to find a general pattern with the idea of congruence for this sequence.

Is $3n \equiv 3 \quad \pmod 1$ correct?

Thanks

Answer 1

We have the superposition of two sequences

• $1+4k \to 1,5,9,13,...$
• $2+4j \to 2,6,10,14,...$

then $a_n\equiv 1,2 \pmod 4$.