A214647 a(n) = (n^n + n^2)/2.

1, 4, 18, 136, 1575, 23346, 411796, 8388640, 193710285, 5000000050, 142655835366, 4458050224200, 151437553296211, 5556003412779106, 218946945190429800, 9223372036854775936, 413620130943168382233, 19673204037648268787874, 989209827830156794562170, 52428800000000000000000200

Offset: 1

Author

Alex Ratushnyak, Jul 24 2012

Keywords

• nonn
• easy

Examples

			a(3) = (3^3 + 3^2)/2 = (27+9)/2 = 18.
		

Crossrefs

Cf. A000290, A000312, A117694.

Programs

Mathematica

a[n_]:=(n^n + n^2)/2; Array[a,20] (* Stefano Spezia, Aug 19 2024 *)

Python

print([int((n**n+n**2)/2) for n in range(1,20)])