Guess 10: 4, 10, 14, 24, 38, 62... It needs a higher 2nd term, but not much higher.
Guess 12: 4, 12, 16, 28, 44, 72... It needs a lower 2nd term. The only lower integer is 11. Try it. Hopefully it isn't some number plus fraction like 11.5.
4, 11, 15, 26, 41, 67... 11 works.