#### Abstract

We derive some interesting identities and arithmetic properties of Bernoulli and Euler polynomials from the orthogonality of Hermite polynomials. Let be the -dimensional vector space over . Then we show that is a good basis for the space for our purpose of arithmetical and combinatorial applications.

#### 1. Introduction

As is well known, the Euler polynomials, , are defined by the generating function as follows: (see ), with the usual convention about replacing by .

In the special case, , is called the nth Euler number. From (1.1) and definition of Euler numbers, we note that with the usual convention about replacing by .

The Bernoulli numbers are defined as (see ), where is a Kronecker symbol.

As is well known, Bernoulli polynomials are also defined by with the usual convention about replacing by (see [1, 1518]).

The Hermite polynomials are defined by the generating function as follows: (see [5, 19]), with the usual convention about replacing by .

From (1.5), we can derive the following identities:

Let us consider two operators as follows:

By (1.7), we get . In particular, if we take , then we have

We note that

From (1.8), we note that

Thus, by (1.10), we get (see [5, 1923]). In the special case, , are called the Hermite numbers.

From (1.5), we can derive the following identities: (cf. [5, 19]), with the usual convention about replacing by . It is easy to show that

By comparing coefficients on the both sides of (1.13), we get where . From (1.12), we have

Let be the -dimensional vector space over . Probably, is the most natural basis for this space. But is also a good basis for the space , for our purpose of arithmetical and combinatorial applications.

For , for some uniquely determined .

The purpose of this paper is to develop methods for computing from the information of . By using these methods, we define some interesting identities.

#### 2. Properties of Hermite Polynomials

From (1.5) and (1.13), we note that

Thus, by (2.1), we obtain the following recurrence formula.

Proposition 2.1. For , one has

By, (1.5), we get

From (2.3), we can derive the following reflection symmetric identity of :

By (1.5), we easily see that

Thus, by (1.5) and (2.5), we get

Thus, by (2.6) and (2.7), we get

From (1.15) and (2.9), we note that

Differentiating on both sides, we have

Thus, we have

From (2.12), we note that is a solution of the following second-order linear differential equation:

From (1.5), we note that

Thus, by (2.14), we get

#### 3. Main Results

By (1.6), we easily get

From (3.1), we note that

It is easy to show that where . By (3.3), we get

From (3.2), we note that are orthogonal basis for the space with respect to the inner product

For , the polynomial is given by where

Let us take . For , we compute in (3.6) as follows

Let . Then we have

Therefore, by (3.6), (3.8), and (3.9), we obtain the following proposition.

Proposition 3.1. One has

Let us take . From (3.4), can be rewritten by where

By integrating by parts, we get

Thus, from (3.11) and (3.13), we have

Therefore, by (3.11) and (3.14), we obtain the following theorem.

Theorem 3.2. For , one has

Remark 3.3. Let us take . Then, by the same method, we obtain the following identity:

Now, we consider . From (3.6), we note that can be rewritten as where

By integrating by parts, we get

From (3.17) and (3.19), we note that

Therefore, by (3.17) and (3.20), we obtain the following theorem.

Theorem 3.4. For , one has

From Theorem 3.4, we note that

Thus, we have, for ,

Let with . Then we easily see that

Let us consider the following polynomial of degree in :

From (3.6), we note that can be rewritten as where

In , it is known that

From (3.23) and (3.29), we have the following:

By (3.24) and (3.30), we get

For , we have

Therefore, by (3.27) and (3.32), we obtain the following theorem.

Theorem 3.5. For , one has

#### Acknowledgment

This research was supported by Basic Science Research Program through the National Research Foundation of Korea NRF funded by the Ministry of Education, Science and Technology 2012R1A1A2003786.