A177009 a(n) = n^n - A002275(n).

0, -7, -84, -855, -7986, -64455, -287568, 5666105, 276309378, 8888888889, 274200559500, 8804989337145, 301763995481142, 11100895714446905, 437782779269748264, 18445632962598440505, 827229150775225653066

Offset

1,2

Comments

20^20-11111111111111111111=104857588888888888888888889 is the only known prime term of this sequence. Next such prime has more than 40000 digits (n>10000)!

Links

Robert Israel, Table of n, a(n) for n = 1..386

Formula

a(n) = n^n - (10^n-1)/9. - Robert Israel, Oct 23 2016

Example

a(2) = 2^2-11 = -7, a(8) = 8^8-11111111 = 5666105.

Maple

seq(n^n - (10^n-1)/9. n=1..20); # Robert Israel, Oct 23 2016

Mathematica

Table[n^n - (10^n - 1)/9, {n, 17}]

Crossrefs

Cf. A000312, A002275, A177010.

Sequence in context: A027819 A269895 A272496 * A099674 A067413 A370779

Adjacent sequences: A177006 A177007 A177008 * A177010 A177011 A177012

Keyword

easy,sign,base

Author

Ali Heydarian (mymontain(AT)yahoo.com), May 13 2010

Status

approved