Let $b \geq 2$ be an integer and denote by $s_b(m)$ the sum of the digits of the positive integer $m$ when is written in base $b$. We prove that $s_b(n!) > C_b \log n \log \log \log n$ for each integer $n > e^e$, where $C_b$ is a positive constant depending only on $b$. This improves by a factor $\log \log \log n$ a previous lower bound for $s_b(n!)$ given by Luca. We prove also the same inequality but with $n!$ replaced by the least common multiple of $1,2,\ldots,n$.

On the sum of digits of the factorial

SANNA, CARLO
2015-01-01

Abstract

Let $b \geq 2$ be an integer and denote by $s_b(m)$ the sum of the digits of the positive integer $m$ when is written in base $b$. We prove that $s_b(n!) > C_b \log n \log \log \log n$ for each integer $n > e^e$, where $C_b$ is a positive constant depending only on $b$. This improves by a factor $\log \log \log n$ a previous lower bound for $s_b(n!)$ given by Luca. We prove also the same inequality but with $n!$ replaced by the least common multiple of $1,2,\ldots,n$.
2015
147
836
841
http://www.elsevier.com/inca/publications/store/6/2/2/8/9/4/index.htt
https://arxiv.org/abs/1409.4912
Base b representation; Factorial; Sum of digits; Algebra and Number Theory
Sanna, Carlo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1622118
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