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A108398
a(n) = n*(1 + n^n)/2.
4
0, 1, 5, 42, 514, 7815, 139971, 2882404, 67108868, 1743392205, 50000000005, 1569214188366, 53496602689542, 1968688192849651, 77784047778906119, 3284204177856445320, 147573952589676412936, 7031542226033862495513
OFFSET
0,3
LINKS
FORMULA
a(n) = A108396(n,n).
E.g.f.: (exp(x) * x - LambertW(-x)/(1 + LambertW(-x))^3) / 2. - Vaclav Kotesovec, Jan 03 2019
PROG
(Magma) [n*(1+n^n)/2: n in [0..25]]; // Vincenzo Librandi, Apr 29 2011
(Haskell)
a108398 n = n * (1 + n ^ n) `div` 2 -- Reinhard Zumkeller, Mar 31 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 02 2005
STATUS
approved