A classical theorem of Kempner states that the sum of the reciprocals of positive integers with missing decimal digits converges. This result is extended to much larger families of “missing digits” sets of positive integers with convergent harmonic series.

中文翻译：

---

缺少数字的收敛整数系列

肯普纳的一个经典定理指出，缺少十进制数字的正整数的倒数之和收敛。这个结果被扩展到更大的具有收敛调和级数的正整数组的“缺失数字”组。