OFFSET
0,2
FORMULA
Conjecture: (n+1)*a(n) +(-7*n+2)*a(n-1) +(11*n-13)*a(n-2) +(-13*n+38)*a(n-3) +12*(n-4)*a(n-4) +4*(-n+5)*a(n-5)=0. - R. J. Mathar, Feb 29 2016
EXAMPLE
a(2)=2*1*2+2+1=7. a(3)=2*1*7+2+2^2+1+1=22. a(4)=2*1*22+2+2*2*7+2+1=77.
MAPLE
l:=1: : k := 1 : m :=2: d(0):=1:d(1):=m: for n from 1 to 32 do d(n+1):=sum(d(p)*d(n-p)+k, p=0..n)+l:od :
taylor((1-sqrt(1-4*z*(d(0)-z*d(0)^2+z*m+(k+l)*z^2/(1-z)+k*z^2/(1-z)^2)))/(2*z), z=0, 34); seq(d(n), n=0..32);
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Richard Choulet, Apr 21 2010
STATUS
approved