OFFSET
1,2
FORMULA
a(n) = Sum_{m=0..n-1} A142963(n,m).
a(n) = Sum_{k=1..n} A211399(n,k)*2^(k-1). - Philippe Deléham, Feb 12 2013
G.f.: 1 + 2*Sum_{n = 1..inf} a(n)*x^n = 1/(1-2*x/(1-x/(1-2*3*x/(1-2*x/(1-2*5*x/(1-3*x/(1-2*7*x/(1-4*x/(1-...))))))))) (continued fraction). - Philippe Deléham, Feb 12 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Sep 15 2008
STATUS
approved