A127691 a(n) = (2*n+1)^n-(2*n-1)^n-(2*n)^n.

-1, 0, 0, 2, 64, 2002, 69264, 2697354, 117899520, 5740530914, 308814720400, 18213955960378, 1169672907313728, 81286160430474066, 6080123714344570128, 487166244246501489002, 41636260100744439399424, 3781449867356996500139458, 363724112817207189865471248

Offset

0,4

Comments

Theorem: (2*n+1)^n-(2*n-1)^n-(2*n)^n > 0 for n >= 3.

References

D. S. Mitrinovic, Analytic Inequalities, Springer-Verlag, 1970; p. 192, 3.1.13.

Links

Table of n, a(n) for n=0..18.

Crossrefs

Sequence in context: A134939 A217268 A122603 * A013822 A010047 A187548

Adjacent sequences: A127688 A127689 A127690 * A127692 A127693 A127694

Keyword

sign

Author

N. J. A. Sloane, Apr 03 2007

Status

approved