Open Access

Weak harmonic Maass forms of weight 5/2 and a mock modular form for the partition function

Research in Number Theory20151:10

Received: 12 March 2015

Accepted: 3 June 2015

Published: 2 December 2015


We construct a natural basis for the space of weak harmonic Maass forms of weight 5/2 on the full modular group. The nonholomorphic part of the first element of this basis encodes the values of the ordinary partition function p(n). We obtain a formula for the coefficients of the mock modular forms of weight 5/2 in terms of regularized inner products of weakly holomorphic modular forms of weight −1/2, and we obtain Hecke-type relations among these mock modular forms.