OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = (n-1)*(n^2 + 5*n + 2)/2.
G.f.: x^2*(x-2)*(x-4)/(1-x)^4. - Colin Barker, Mar 18 2012
a(n) = (n-1)*A034856(n+1). - R. J. Mathar, Aug 22 2016
MAPLE
seq(sum(j, j=binomial(n+1, 2)+n-1..binomial(n+2, 2)+n-2) - binomial(n+2, 2)-n+1, n=1..50); # Emeric Deutsch, Aug 27 2005
MATHEMATICA
Table[(n^3 + 4n^2 - 3n - 2)/2, {n, 41}] (* Robert G. Wilson v, Aug 27 2005 *)
PROG
(Magma) [(n^3 + 4*n^2 - 3*n - 2)/2: n in [1..60]]; // Vincenzo Librandi, May 21 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amarnath Murthy, Aug 17 2005
EXTENSIONS
Edited and extended by Emeric Deutsch and Robert G. Wilson v, Aug 27 2005
STATUS
approved