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.

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, 29, 30, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 85

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• base
• easy

Comments

Numbers without digit 7 in base 8. Complement of A337239. - François Marques, Oct 13 2020

Examples

			a(48)=54 because 48 is 66_7 in base 7 and 66_8=54. - _François Marques_, Oct 13 2020
		

Links

• François Marques, Table of n, a(n) for n = 0..10000 (first 1000 terms from Clark Kimberling)

Crossrefs

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).

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).

Programs

Mathematica

Table[FromDigits[RealDigits[n, 7], 8], {n, 0, 100}] (* Clark Kimberling, Aug 14 2012 *)

PARI

a(n) = fromdigits(digits(n, 7), 8); \\ François Marques, Oct 13 2020

Python

from gmpy2 import digits
def A037474(n): return int(digits(n,7),8) # Chai Wah Wu, Dec 04 2024

Extensions

Offset changed to 0 by Clark Kimberling, Aug 14 2012