OFFSET
0,2
COMMENTS
The moments, i.e. E(X^n) = int(x^n * p(x), x = 0..infinity) for n > 0, of the probability density function p(x) = 2*x*E(x, 1, 1), see A163931, lead to this sequence.
LINKS
J. W. Meijer and N. H. G. Baken, The Exponential Integral Distribution, Statistics and Probability Letters, Volume 5, No.3, April 1987. pp 209-211.
FORMULA
EXAMPLE
The first few moments of p(x) are: 1, 4/3, 3, 48/5, 40, 1440/7, … .
MAPLE
a := proc(n): numer(2*(n+1)!/(n+2)) end: seq(a(n), n=0..20);
PROG
(PARI) a(n) = numerator(2*(n+1)!/(n+2)) \\ Felix Fröhlich, Jun 09 2016
CROSSREFS
KEYWORD
nonn,frac,easy
AUTHOR
Johannes W. Meijer, Jun 08 2016
STATUS
approved