The pattern alternates between subtracting 11 and adding 3 on odd/even positions. Odd positions: 23-11=12, 12+3=15. Even positions: 5-2=3, 3+2=5. Continuing the even position pattern (add 2): 3+2=5. Alternatively, viewing it as two interleaved sequences: 23, 12, 15 (subtract 11, add 3) and 5, 3, ? (subtract 2, add 2), the next term is 3+2=5.