login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A155672
11^n-9^n+1^n
2
1, 3, 41, 603, 8081, 102003, 1240121, 14704203, 171312161, 1970527203, 22450640201, 253930611003, 2855998840241, 31980846315603, 356873041128281, 3971357037321003, 44096709674720321, 488769846799627203
OFFSET
0,2
FORMULA
G.f.: 1/(1-11*x)-1/(1-9*x)+1/(1-x). E.g.f.: e^(11*x)-e^(9*x)+e^x.
a(n)=20*a(n-1)-99*a(n-2)+80 with a(0)=1, a(1)=3 [From Vincenzo Librandi, Jul 21 2010]
MATHEMATICA
Table[11^n-9^n+1, {n, 0, 30}] (* or *) LinearRecurrence[{21, -119, 99}, {1, 3, 41}, 30] (* Harvey P. Dale, May 07 2019 *)
KEYWORD
nonn
AUTHOR
Mohammad K. Azarian, Feb 01 2009
STATUS
approved