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A214647
a(n) = (n^n + n^2)/2.
3
1, 4, 18, 136, 1575, 23346, 411796, 8388640, 193710285, 5000000050, 142655835366, 4458050224200, 151437553296211, 5556003412779106, 218946945190429800, 9223372036854775936, 413620130943168382233, 19673204037648268787874, 989209827830156794562170, 52428800000000000000000200
OFFSET
1,2
EXAMPLE
a(3) = (3^3 + 3^2)/2 = (27+9)/2 = 18.
MATHEMATICA
a[n_]:=(n^n + n^2)/2; Array[a, 20] (* Stefano Spezia, Aug 19 2024 *)
PROG
(Python) print([int((n**n+n**2)/2) for n in range(1, 20)])
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alex Ratushnyak, Jul 24 2012
STATUS
approved