On logarithmically Benford Sequences

Authors:
Evan Chen, Peter S. Park and Ashvin A. Swaminathan

Journal:
Proc. Amer. Math. Soc. **144** (2016), 4599-4608

MSC (2010):
Primary 11F11, 11N05

DOI:
https://doi.org/10.1090/proc/13112

Published electronically:
July 22, 2016

MathSciNet review:
3544512

Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Let $\mathcal {I} \subset \mathbb {N}$ be an infinite subset, and let $\{a_i\}_{i \in \mathcal {I}}$ be a sequence of nonzero real numbers indexed by $\mathcal {I}$ such that there exist positive constants $m, C_1$ for which $|a_i| \leq C_1 \cdot i^m$ for all $i \in \mathcal {I}$. Furthermore, let $c_i \in [-1,1]$ be defined by $c_i = \frac {a_i}{C_1 \cdot i^m}$ for each $i \in \mathcal {I}$, and suppose the $c_i$’s are equidistributed in $[-1,1]$ with respect to a continuous, symmetric probability measure $\mu$. In this paper, we show that if $\mathcal {I} \subset \mathbb {N}$ is not too sparse, then the sequence $\{a_i\}_{i \in \mathcal {I}}$ fails to obey Benford’s Law with respect to arithmetic density in any sufficiently large base, and in fact in any base when $\mu ([0,t])$ is a strictly convex function of $t \in (0,1)$. Nonetheless, we also provide conditions on the density of $\mathcal {I} \subset \mathbb {N}$ under which the sequence $\{a_i\}_{i \in \mathcal {I}}$ satisfies Benford’s Law with respect to logarithmic density in every base.

As an application, we apply our general result to study Benford’s Law-type behavior in the leading digits of Frobenius traces of newforms of positive, even weight. Our methods of proof build on the work of Jameson, Thorner, and Ye, who studied the particular case of newforms without complex multiplication.

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Additional Information

**Evan Chen**

Affiliation:
Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02138

MR Author ID:
1158569

Email:
evanchen@mit.edu

**Peter S. Park**

Affiliation:
Department of Mathematics, Princeton University, Princeton, New Jersey 08544

MR Author ID:
1046046

Email:
pspark@math.princeton.edu

**Ashvin A. Swaminathan**

Affiliation:
Department of Mathematics, Harvard College, Cambridge, Massachusetts 02138

Email:
aaswaminathan@college.harvard.edu

Received by editor(s):
January 8, 2016

Published electronically:
July 22, 2016

Communicated by:
Ken Ono

Article copyright:
© Copyright 2016
American Mathematical Society