OFFSET
0,3
COMMENTS
With leading 0 and offset 1, number of permutations beginning with 21 and avoiding 3-12. - Ralf Stephan, Apr 25 2004
LINKS
N. J. A. Sloane, Transforms
Sergey Kitaev, Generalized pattern avoidance with additional restrictions, Sem. Lothar. Combinat. 48 (2003), Article B48e.
Sergey Kitaev, Partially Ordered Generalized Patterns, Discrete Math. 298(1-3) (2005), 212-229.
Sergey Kitaev and Toufik Mansour, Simultaneous avoidance of generalized patterns, arXiv:math/0205182 [math.CO], 2002.
FORMULA
With offset 1, e.g.f.: x + exp(exp(x)) * int[0..x, exp(-exp(t))*sum(n>=1, t^n/n!) dt]. - Ralf Stephan, Apr 25 2004
MATHEMATICA
max = 23; f[x_] = x + Exp[Exp[x]]*Integrate[Exp[-Exp[t]]*Sum[t^n/n!, {n, 1, max}], {t, 0, x}]; Rest[ CoefficientList[ Series[f[x], {x, 0, max}], x]*Range[0, max]!] (* Jean-François Alcover, Aug 07 2012, after Ralf Stephan *)
CROSSREFS
KEYWORD
nonn,nice,easy,eigen
AUTHOR
Joe K. Crump (joecr(AT)carolina.rr.com)
EXTENSIONS
Last digit of a(22) corrected by Jean-François Alcover, Aug 07 2012
STATUS
approved