OFFSET
1,2
REFERENCES
P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem, Phys. Lett. A 309 (2003) 198-205.
M. Schork, On the combinatorics of normal ordering bosonic operators and deforming it, J. Phys. A 36 (2003) 4651-4665.
LINKS
P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem.
FORMULA
MATHEMATICA
a[n_] := Sum[(-1)^k FactorialPower[k, 4]^n/k!, {k, 2, Infinity}]*E; Array[a, 12] (* Jean-François Alcover, Sep 01 2016 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Wolfdieter Lang, Dec 01 2003
STATUS
approved