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

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

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Formula

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

Example

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

Prog

(Python)
for n in range(1, 22):
    print (n*n + n**n)/2,

Crossrefs

Cf. A117694.

Sequence in context: A356542 A371038 A065857 * A156445 A304997 A060841

Adjacent sequences: A214644 A214645 A214646 * A214648 A214649 A214650

Keyword

nonn,easy

Author

Alex Ratushnyak, Jul 24 2012

Status

approved