The expansion of the infinite product (1–x)(1–xx)(1–x3)(1–x4)(1–x5)(1–x6) etc. into a single series
This paper does exactly what the title says it does. It expands the given series to arrive at the familiar "pentagonal number" expansion, now known as the pentagonal number theorem, and recalls its application to partition numbers. (Based on Jordan Bell's translation abstract.)
Original Source Citation
Acta Academiae Scientiarum Imperialis Petropolitanae, Volume 1780: I, pp. 47-55.
Opera Omnia Citation
Series 1, Volume 3, pp.472-479.