If we begin with the first term, 2, mult. it by 4 and then subtract 3, we get 5 (not 4, as shown).
If we begin with 4, mult. it by 4 and then subtract 3, we get 13. This agrees with the terms of the given sequence.
If we begin with 13, mult. it by 4 and then subtract 3, we get 49. This agrees with the terms of the given sequence.
Remove the first term, 2, and then the remaining terms follow the given procedure for finding terms.