OFFSET
0,5
LINKS
H. S. Wilf, A lot of toast, with a side order of roast, manuscript, Jan 04 2002.
Index entries for linear recurrences with constant coefficients, signature (25,-239,1115,-2664,3060,-1296).
FORMULA
G.f.: x^3*(1+11*x-36*x^2-36*x^3)/((1-x)*(1-2*x)*(1-3*x)*(1-4*x)*(1-6*x)*(1-9*x)).
a(n) = (3^n - 3*2^n + 3)^2/36 for n>0. - Charles R Greathouse IV, Jan 03 2013
MATHEMATICA
StirlingS2[Range[0, 30], 3]^2 (* Harvey P. Dale, Jan 03 2013 *)
PROG
(Sage)[stirling_number2(n, 3)^2for n in range(0, 23)] # Zerinvary Lajos, Mar 14 2009
(PARI) a(n)=(3^n-3<<n+3)^2/36 \\ Charles R Greathouse IV, Jan 03 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Feb 08 2008
EXTENSIONS
Definition corrected (exponent changed from 3 to 2) by Harvey P. Dale, Jan 03 2013
STATUS
approved