Find the wrong number in following number series. 156 , 299 , 494 , 749 , 1070 , 1471.

The differences between consecutive terms are squares of consecutive primes. The differences are 143, 195, 255, 321 and 401; these are not squares of primes, but are instead 12 squared minus 1, 14 squared minus 1, 16 squared minus 1, 18 squared minus 1 and 20 squared minus 1. The correct difference between 749 and the next term should be 20 squared minus 1, which is 399; adding 399 to 749 gives 1148. Since the given term is 1070, it is the wrong number.

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