# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a214647 Showing 1-1 of 1 %I A214647 #17 Aug 20 2024 09:08:57 %S A214647 1,4,18,136,1575,23346,411796,8388640,193710285,5000000050, %T A214647 142655835366,4458050224200,151437553296211,5556003412779106, %U A214647 218946945190429800,9223372036854775936,413620130943168382233,19673204037648268787874,989209827830156794562170,52428800000000000000000200 %N A214647 a(n) = (n^n + n^2)/2. %e A214647 a(3) = (3^3 + 3^2)/2 = (27+9)/2 = 18. %t A214647 a[n_]:=(n^n + n^2)/2; Array[a,20] (* _Stefano Spezia_, Aug 19 2024 *) %o A214647 (Python) print([int((n**n+n**2)/2) for n in range(1,20)]) %Y A214647 Cf. A000290, A000312, A117694. %K A214647 nonn,easy %O A214647 1,2 %A A214647 _Alex Ratushnyak_, Jul 24 2012 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE