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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 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.)