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A125837
Numbers whose base 8 or octal representation is 6666666......6.
4
0, 6, 54, 438, 3510, 28086, 224694, 1797558, 14380470, 115043766, 920350134, 7362801078, 58902408630, 471219269046, 3769754152374, 30158033218998, 241264265751990, 1930114126015926, 15440913008127414, 123527304065019318, 988218432520154550, 7905747460161236406
OFFSET
1,2
FORMULA
a(n) = 6*(8^(n-1) -1)/7 = 6*A023001(n-1).
a(n) = 8*a(n-1) + 6 for n>1, a(1)=0. - Vincenzo Librandi, Oct 03 2010
G.f.: 6*x^2/( (1-x)*(1-8*x) ). - R. J. Mathar, Oct 07 2016
E.g.f.: 6*(exp(8*x) - exp(x))/7. - G. C. Greubel, Aug 03 2019
a(n) = -1 + A083068(n-1). - Alois P. Heinz, May 20 2023
MAPLE
seq(6*(8^n-1)/7, n=0..30);
MATHEMATICA
FromDigits[#, 8]&/@Table[Table[6, {i}], {i, 0, 30}] (* Harvey P. Dale, Mar 19 2011 *)
6*(8^(Range[30]-1) -1)/7 (* G. C. Greubel, Aug 03 2019 *)
PROG
(PARI) vector(30, n, 6*(8^(n-1)-1)/7) \\ G. C. Greubel, Aug 03 2019
(Magma) [6*(8^(n-1)-1)/7: n in [1..30]]; // G. C. Greubel, Aug 03 2019
(Sage) [6*(8^(n-1)-1)/7 for n in (1..30)] # G. C. Greubel, Aug 03 2019
(GAP) List([1..30], n-> 6*(8^(n-1)-1)/7); # G. C. Greubel, Aug 03 2019
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Zerinvary Lajos, Feb 03 2007
STATUS
approved