OFFSET
0,2
COMMENTS
(1 + 3x + 9x^2 + ...) = (1 + 3x + 6x^2 + 10x^3 + ...) * (1 + 3x^2 + 6x^3 + 10x^4 + ...). - Gary W. Adamson, Jul 27 2010
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: (x^4 - 4*x^3 + 6*x^2 - 3*x + 1) / (1-x)^6.
MAPLE
a := n-> 1+ (144+ (50+ (35+ (10+ n) *n) *n) *n) *n/120: seq (a(n), n=0..40);
PROG
(Magma) [1 + (144 + (50 + (35 + (10 + n)*n)*n)*n)*n/120: n in [0..40]]; // Vincenzo Librandi, May 19 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 03 2008
STATUS
approved