A007094 - OEIS

%I M0498 #54 Jun 29 2021 02:33:47

%S 0,1,2,3,4,5,6,7,10,11,12,13,14,15,16,17,20,21,22,23,24,25,26,27,30,

%T 31,32,33,34,35,36,37,40,41,42,43,44,45,46,47,50,51,52,53,54,55,56,57,

%U 60,61,62,63,64,65,66,67,70,71,72,73,74,75,76,77,100,101,102,103,104,105,106,107,110,111

%N Numbers in base 8.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Nathaniel Johnston, <a href="/A007094/b007094.txt">Table of n, a(n) for n = 0..10000</a>

%H Wikipedia, <a href="http://www.wikipedia.org/wiki/Octal">Octal</a>

%H R. G. Wilson, V, <a href="/A007088/a007088.pdf">Letter to N. J. A. Sloane, Sep. 1992</a>

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.

%F a(0) = 0; a(n) = 10*a(n/8) if n == 0 (mod 8); a(n) = a(n-1) + 1 otherwise. - _Benoit Cloitre_, Dec 22 2002

%F G.f.: sum(d>=0, 10^d*(x^(8^d) +2*x^(2*8^d) +3*x^(3*8^d) +4*x^(4*8^d) +5*x^(5*8^d) +6*x^(6*8^d) +7*x^(7*8^d)) * (1-x^(8^d)) / ((1-x^(8^(d+1)))*(1-x))). - _Robert Israel_, Aug 03 2014

%p A007094 := proc(n) local l: if(n=0)then return 0: fi: l:=convert(n,base,8): return op(convert(l,base,10,10^nops(l))): end: seq(A007094(n), n=0..66); # _Nathaniel Johnston_, May 06 2011

%t Table[FromDigits[IntegerDigits[n, 8]], {n, 0, 70}]

%o (PARI) a(n)=if(n<1,0,if(n%8,a(n-1)+1,10*a(n/8)))

%o (PARI) apply( A007094(n)=fromdigits(digits(n,8)), [0..77]) \\ _M. F. Hasler_, Nov 18 2019

%o (Haskell)

%o a007094 0 = 0

%o a007094 n = 10 * a007094 n' + m where (n', m) = divMod n 8

%o -- _Reinhard Zumkeller_, Aug 29 2013

%o (Python)

%o def a(n): return int(oct(n)[2:])

%o print([a(n) for n in range(74)]) # _Michael S. Branicky_, Jun 28 2021

%Y Cf. A057104; A000042 (base 1), A007088 (base 2), A007089 (base 3), A007090 (base 4), A007091 (base 5), A007092 (base 6), A007093 (base 7), A007095 (base 9).

%K nonn,easy,base

%O 0,3

%A _N. J. A. Sloane_, _Robert G. Wilson v_