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A125836 Numbers whose base 8 or octal representation is 555555555......5. 1
0, 5, 45, 365, 2925, 23405, 187245, 1497965, 11983725, 95869805, 766958445, 6135667565, 49085340525, 392682724205, 3141461793645, 25131694349165, 201053554793325, 1608428438346605, 12867427506772845, 102939420054182765 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..20.

Index entries for linear recurrences with constant coefficients, signature (9,-8).

FORMULA

a(n)=5*(8^(n-1)-1)/7 = 5*A023001(n-1).

a(n)=8*a(n-1)+5 (with a(1)=0) [From Vincenzo Librandi, Sep 30 2010]

G.f. 5*x^2 / ( (8*x-1)*(x-1) ). - R. J. Mathar, Sep 30 2013

EXAMPLE

Octal...............decimal

0........................0

5........................5

55......................45

555....................365

5555..................2925

55555................23405

555555..............187245

5555555............1497965

55555555..........11983725

555555555.........95869805

5555555555.......766958445

etc. ...............etc.

MAPLE

seq(5*(8^n-1)/7, n=0..20);

CROSSREFS

Sequence in context: A268219 A272494 A185009 * A001260 A088505 A067403

Adjacent sequences:  A125833 A125834 A125835 * A125837 A125838 A125839

KEYWORD

easy,nonn

AUTHOR

Zerinvary Lajos, Feb 03 2007

STATUS

approved

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Last modified June 20 05:01 EDT 2019. Contains 324229 sequences. (Running on oeis4.)