Published online by Cambridge University Press: 08 January 2020
Let $\overline{t}(n)$ be the number of overpartitions in which (i) the difference between successive parts may be odd only if the larger part is overlined and (ii) if the smallest part is odd then it is overlined. Ramanujan-type congruences for $\overline{t}(n)$ modulo small powers of $2$ and $3$ have been established. We present two infinite families of congruences modulo $5$ and $27$ for $\overline{t}(n)$, the first of which generalises a recent result of Chern and Hao [‘Congruences for two restricted overpartitions’, Proc. Math. Sci. 129 (2019), Article 31].
The first author was supported by the National Natural Science Foundation of China (No. 11871246), the Natural Science Foundation of Fujian Province of China (No. 2019J01328) and the Program for New Century Excellent Talents in Fujian Province University (No. B17160).