A062810 a(n) = Sum_{i=1..n} i^(n - i) + (n - i)^i.

1, 3, 7, 17, 45, 131, 419, 1465, 5561, 22755, 99727, 465537, 2303829, 12037571, 66174411, 381560425, 2301307841, 14483421859, 94909491607, 646309392369, 4565559980989, 33401808977411, 252713264780595, 1974606909857945

Offset: 1

Author

Olivier Gérard, Jun 23 2001

Keywords

• nonn
• easy

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..600

Crossrefs

Cf. A003101, A026898, A062811, A062812.

Programs

Mathematica

Sum[i^(n - i) + (n - i)^i, {i, 1, n}]

PARI

a(n) = sum(i=1, n, i^(n-i) + (n-i)^i); \\ Michel Marcus, Mar 24 2019

Formula

a(n) = 2 * A026898(n-1) - 1.

a(n) = 2 * A003101(n-1) + 1.