|
Search: id:A047854
|
|
| |
|
| 1, 2, 11, 92, 821, 7382, 66431, 597872, 5380841, 48427562, 435848051, 3922632452, 35303692061, 317733228542, 2859599056871, 25736391511832, 231627523606481, 2084647712458322
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
FORMULA
|
(9^n + 7)/8. - Ralf Stephan, Feb 14 2004
a(0)= 1, a(1)= 2, a(n)= 10*a(n-1)-9*a(n-2) for n>1. G.f.: (1-8x)/(1-10x+9x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 06 2009]
a(n)=9*a(n-1)-7 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 31 2009]
|
|
EXAMPLE
|
For n=2, a(2)=9*1-7=2; n=3, a(3)=9*2-7=11; n=4, a(4)=9*11-7=92 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 31 2009]
|
|
MAPLE
|
a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=9*a[n-1]+1 od: seq(a[n]+1, n=0..17); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 20 2008
|
|
MATHEMATICA
|
a = {}; ZZ = 1; Do[ZZ = ZZ + 3^(2x); AppendTo[a, ZZ], {x, 0, 17}]; a - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 03 2007
|
|
CROSSREFS
|
n-th difference of a(n), a(n-1), ..., a(0) is 8^(n-1) for n=1, 2, 3, ...
Sequence in context: A004677 A094955 A143870 this_sequence A122708 A005366 A068392
Adjacent sequences: A047851 A047852 A047853 this_sequence A047855 A047856 A047857
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
Clark Kimberling (ck6(AT)evansville.edu)
|
|
|
Search completed in 0.005 seconds
|
