A217009 Multiples of 7 in base 8.

7, 16, 25, 34, 43, 52, 61, 70, 77, 106, 115, 124, 133, 142, 151, 160, 167, 176, 205, 214, 223, 232, 241, 250, 257, 266, 275, 304, 313, 322, 331, 340, 347, 356, 365, 374, 403, 412, 421, 430, 437, 446, 455, 464, 473, 502, 511, 520, 527, 536, 545, 554, 563

Offset: 1

Author

Jon Perry, Sep 23 2012

Keywords

• nonn
• base
• easy

Comments

Digit sum is always divisible by 7.

Reinterpreting this sequence in base 10, these are numbers of the form 9n + 7 but with all numbers containing 8s and/or 9s removed. - Alonso del Arte, Sep 23 2012

Examples

			a(10) = 106 because 7 * 10 = 70, or 1 * 8^2 + 0 * 8^1 + 6 * 8^0 = 64 + 6 = 106_8.
		

Crossrefs

Cf. A216994, A216995, A216996, A216997, A216998.

Cf. A008589.

Programs

JavaScript

k = 7;
for (i = 1; i <= 200; i++) {
x = i * k;
document.write(x.toString(k + 1) + ", ");
}

Mathematica

Table[BaseForm[7*n, 8], {n, 100}] (* Alonso del Arte, Sep 23 2012 *)
Select[9*Range[0, 99] + 7, DigitCount[#, 10, 8] == 0 && DigitCount[#, 10, 9] == 0 &] (* Alonso del Arte, Sep 23 2012 *)
Table[FromDigits[IntegerDigits[7*n, 8]], {n, 100}] (* T. D. Noe, Sep 24 2012 *)

Formula

a(n) = A007094(A008589(n)). -