OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Aviezri S. Fraenkel and Urban Larsson, Playability and arbitrarily large rat games, arXiv:1705.03061 [math.CO], 2017. See p. 27.
Luis Manuel Rivera, Integer sequences and k-commuting permutations, arXiv preprint arXiv:1406.3081 [math.CO], 2014-2015.
FORMULA
a(n) = (n^3 - 3n^2 + 8n + 6)/6 fits all listed terms. - John W. Layman, Mar 13 1999
Empirical G.f.: -x*(x^3 - 5*x^2 + 5*x - 2) / (x - 1)^4. - Colin Barker, Sep 19 2012
MATHEMATICA
a=2; s=3; lst={0, 1, s}; Do[a+=n; s+=a; AppendTo[lst, s], {n, 2, 4!, 1}]; lst+2 (* Vladimir Joseph Stephan Orlovsky, May 24 2009 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Svante Linusson (linusson(AT)math.kth.se)
STATUS
approved