A117694 a(n) = (n^n + n)/2.

1, 3, 15, 130, 1565, 23331, 411775, 8388612, 193710249, 5000000005, 142655835311, 4458050224134, 151437553296133, 5556003412779015, 218946945190429695, 9223372036854775816, 413620130943168382097, 19673204037648268787721

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..380

Formula

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

a(n) = A066068(n)/2, for n > 0.

E.g.f.: (1/2)*(x*exp(x) - LambertW(-x)/(1 + LambertW(-x))). - G. C. Greubel, Jul 23 2023

Mathematica

Table[n^n+n, {n, 30}]/2

Prog

(Magma) [(n+n^n)/2: n in [1..30]]; // G. C. Greubel, Jul 23 2023
(SageMath) [(n+n^n)/2 for n in range(1, 31)] # G. C. Greubel, Jul 23 2023

Crossrefs

Cf. A066068.

Sequence in context: A075475 A074241 A228365 * A264795 A222390 A281186

Adjacent sequences: A117691 A117692 A117693 * A117695 A117696 A117697

Keyword

nonn

Author

Alexander Adamchuk, Apr 12 2006

Status

approved