A214647
a(n) = (n^n + n^2)/2.
Original entry on oeis.org
1, 4, 18, 136, 1575, 23346, 411796, 8388640, 193710285, 5000000050, 142655835366, 4458050224200, 151437553296211, 5556003412779106, 218946945190429800, 9223372036854775936, 413620130943168382233, 19673204037648268787874, 989209827830156794562170, 52428800000000000000000200
Offset: 1
a(3) = (3^3 + 3^2)/2 = (27+9)/2 = 18.
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a[n_]:=(n^n + n^2)/2; Array[a,20] (* Stefano Spezia, Aug 19 2024 *)
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print([int((n**n+n**2)/2) for n in range(1,20)])
A214698
a(n) = (n^n - n^2)/2.
Original entry on oeis.org
0, 0, 9, 120, 1550, 23310, 411747, 8388576, 193710204, 4999999950, 142655835245, 4458050224056, 151437553296042, 5556003412778910, 218946945190429575, 9223372036854775680, 413620130943168381944, 19673204037648268787550, 989209827830156794561809, 52428799999999999999999800
Offset: 1
Cf.
A124797 is essentially equal to (n^n-n)/2.
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[(n^n -n^2)/2: n in [1..30]]; // G. C. Greubel, Jan 08 2024
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A214698:= proc(n)
(n^n-n^2)/2 ;
end proc: # R. J. Mathar, Aug 07 2012
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Table[(n^n-n^2)/2,{n,30}] (* Harvey P. Dale, Dec 25 2022 *)
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for n in range(1, 22):
print((n**n - n*n)//2)
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[(n^n -n^2)/2 for n in range(1,31)] # G. C. Greubel, Jan 08 2024
Showing 1-2 of 2 results.