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Numbers of the form i*8^j-1 (i=1..7, j >= 0).
9

%I #29 May 05 2024 10:41:36

%S 0,1,2,3,4,5,6,7,15,23,31,39,47,55,63,127,191,255,319,383,447,511,

%T 1023,1535,2047,2559,3071,3583,4095,8191,12287,16383,20479,24575,

%U 28671,32767,65535,98303,131071,163839,196607,229375,262143,524287,786431,1048575,1310719,1572863,1835007,2097151

%N Numbers of the form i*8^j-1 (i=1..7, j >= 0).

%C Numbers whose sum of digits in base 8 sets a new record. - _Harvey P. Dale_, Jan 10 2024

%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,8,-8).

%F G.f.: x^2*(x^6+x^5+x^4+x^3+x^2+x+1) / ((x-1)*(8*x^7-1)). [_Colin Barker_, Feb 01 2013]

%t Sort[Flatten[Table[i 8^j-1,{i,1,7},{j,0,7}]]] (* _Harvey P. Dale_, Feb 03 2011 *)

%Y Smallest number whose base b sum of digits is n: A000225 (b=2), A062318 (b=3), A180516 (b=4), A181287 (b=5), A181288 (b=6), A181303 (b=7), this sequence (b=8), A140576 (b=9), A051885 (b=10). - _Jason Kimberley_, Nov 02 2011

%K nonn,easy

%O 1,3

%A _N. J. A. Sloane_, Jan 25 2011