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) = (1/6)*(20*n^3 - 24*n^2 + 10*n).
G.f.: x*(1+x)*(1+9*x)/(1-x)^4. [Colin Barker, May 29 2012]
PROG
(Magma) [(1/6)*(20*n^3-24*n^2+10*n): n in [1..50] ]; // Vincenzo Librandi, Aug 02 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
James A. Record (james.record(AT)gmail.com), Nov 07 2004
EXTENSIONS
Formula corrected by Helena Verrill (verrill(AT)math.lsu.edu), Mar 23 2007
STATUS
approved