cp's OEIS Frontend

A037474 a(n) = Sum{d(i)*8^i: i=0,1,...,m}, where Sum{d(i)*7^i: i=0,1,...,m} is the base 7 representation of n.

%I A037474 #21 Dec 04 2024 13:53:45
%S A037474 0,1,2,3,4,5,6,8,9,10,11,12,13,14,16,17,18,19,20,21,22,24,25,26,27,28,
%T A037474 29,30,32,33,34,35,36,37,38,40,41,42,43,44,45,46,48,49,50,51,52,53,54,
%U A037474 64,65,66,67,68,69,70,72,73,74,75,76,77,78,80,81,82,83,84,85
%N A037474 a(n) = Sum{d(i)*8^i: i=0,1,...,m}, where Sum{d(i)*7^i: i=0,1,...,m} is the base 7 representation of n.
%C A037474 Numbers without digit 7 in base 8. Complement of A337239. - _François Marques_, Oct 13 2020
%H A037474 François Marques, <a href="/A037474/b037474.txt">Table of n, a(n) for n = 0..10000</a> (first 1000 terms from Clark Kimberling)
%e A037474 a(48)=54 because 48 is 66_7 in base 7 and 66_8=54. - _François Marques_, Oct 13 2020
%t A037474 Table[FromDigits[RealDigits[n, 7], 8], {n, 0, 100}] (* _Clark Kimberling_, Aug 14 2012 *)
%o A037474 (PARI) a(n) = fromdigits(digits(n, 7), 8); \\ _François Marques_, Oct 13 2020
%o A037474 (Python)
%o A037474 from gmpy2 import digits
%o A037474 def A037474(n): return int(digits(n,7),8) # _Chai Wah Wu_, Dec 04 2024
%Y A037474 Cf. Numbers with at least one digit b-1 in base b : A074940 (b=3), A337250 (b=4), A337572 (b=5), A333656 (b=6), A337141 (b=7), A337239 (b=8), A338090 (b=9), A011539 (b=10), A095778 (b=11).
%Y A037474 Cf. Numbers with no digit b-1 in base b: A005836 (b=3), A023717 (b=4), A020654 (b=5), A037465 (b=6), A020657 (b=7), this sequence (b=8), A037477 (b=9), A007095 (b=10), A171397 (b=11).
%K A037474 nonn,base,easy
%O A037474 0,3
%A A037474 _Clark Kimberling_
%E A037474 Offset changed to 0 by _Clark Kimberling_, Aug 14 2012