On Stanley's Partition Function

William Y. C. Chen, Kathy Q. Ji, and Albert J. W. Zhu

  Abstract:  Stanley defined a partition function t(n) as the number of partitions λ of n such that the number of odd parts of λ is congruent to the number of odd parts of the conjugate partition λ' modulo 4. We show that t(n) equals the number of partitions of n with an even number of hooks of even length. We derive a closed-form formula for the generating function for the numbers p(n) - t(n). As a consequence, we see that t(n) has the same parity as the ordinary partition function p(n) for any n. A simple combinatorial explanation of this fact is also provided.

  AMS Classification:  05A17

  Keywords:  partition function, Jacobi's triple product identity, hook length

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