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A177009
a(n) = n^n - A002275(n).
3
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
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
KEYWORD
easy,sign,base
AUTHOR
Ali Heydarian (mymontain(AT)yahoo.com), May 13 2010
STATUS
approved