Some new identities of Bernoulli, Euler and Hermite polynomials arising from umbral calculus

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Some new identities of Bernoulli, Euler and Hermite polynomials arising from umbral calculus Dae San Kim1 , Taekyun Kim2* , Dmitry V Dolgy3 and Seog-Hoon Rim4 *

Correspondence: [email protected] 2 Department of Mathematics, Kwangwoon University, Seoul, 139-701, Republic of Korea Full list of author information is available at the end of the article

Abstract In this paper, we derive the identities of higher-order Bernoulli, Euler and Frobenius-Euler polynomials from the orthogonality of Hermite polynomials. Finally, we give some interesting and new identities of several special polynomials arising from umbral calculus. MSC: 05A10; 05A19 Keywords: Bernoulli polynomial; Euler polynomial; Abel polynomial

1 Introduction The Hermite polynomials are defined by the generating function to be 

ext–t = eH(x)t =

∞ 

Hn (x)

n=

tn n!

(.)

with the usual convention about replacing H n (x) by Hn (x) (see []). In the special case, x = , Hn () = Hn are called the nth Hermite numbers. From (.) we have Hn (x) = (H + x)n =

n    n Hn–l xl l . l

(.)

l=

Thus, by (.), we get n! dk Hn–k (x), Hn (x) = k (n)k Hn–k (x) = k k dx (n – k)!

(.)

where (x)k = x(x – ) · · · (x – k + ). As is well known, the Bernoulli polynomials of order r are defined by the generating function to be 

t et – 

r ext =

∞  n=

B(r) n (x)

tn n!

(r ∈ R).

(.)

(r) In the special case, x = , B(r) n () = Bn are called the nth Bernoulli numbers of order r (see [–]).

© 2013 Kim et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Kim et al. Advances in Difference Equations 2013, 2013:73 http://www.advancesindifferenceequations.com/content/2013/1/73

Page 2 of 11

The Euler polynomials of order r are also defined by the generating function to be 

 t e +

r

∞ 

ext =

En(r) (x)

n=

tn n!

(r ∈ R).

(.)

In the special case, x = , En(r) () = En(r) are called the nth Euler numbers of order r. For λ(= ) ∈ C, the Frobenius-Euler polynomials of order r are given by 

–λ et – λ

r ext =

∞ 

Hn(r) (x|λ)

n=

tn n!

(r ∈ R).

(.)

In the special case, x = , Hn(r) (|λ) = Hn(r) (λ) are called the nth Frobenius-Euler numbers of order r (see [–]). The Stirling numbers of the first kind are defined by the generating function to be

(x)n =

n 

S (n, k)xk

(see [, ]),

(.)

k=

and the Stirling numbers of the second kind are given by 

et – 

n

= n!

∞ 

S (l, n)

l=n

tl l!

(see []).

(.)

In [] it is known that H (x), H (x), . . . , Hn (x) from an orthogonal basis for the space   Pn = p(x) ∈ Q[x]| deg p(x) ≤ n

(.)

with respect to the inner product

p (x), p (x) =







e–x p (x)p (x) dx

(see []).

(.)

–∞

For p(x) ∈ Pn , let us assume that

p(x) =

n 

Ck Hk (x).

(.)

k=

Then, from the orthog