Let be the smallest positive integer that is not coprime to any positive integer whose least significant digit is .
For example equals to since it is not coprime to any of . By taking the natural logarithm (log to base ) we obtain when rounded to six digits after the decimal point.
You are also given .
Find . Enter its natural logarithm rounded to six digits after the decimal point.
记 为满足:不与任何个位是 且 的正整数 互质的最小整数。例如:因为 不与 中的任何一个互质,故 。取 自然对数 可得 (四舍五入至小数点后第 6 位)。已知:。
求 。将其取自然对数后四舍五入至小数点后第 6 位。
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