A039109 Numbers whose base-9 representation has the same number of 6's and 7's.

0, 1, 2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 17, 18, 19, 20, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 35, 36, 37, 38, 39, 40, 41, 44, 45, 46, 47, 48, 49, 50, 53, 61, 69, 72, 73, 74, 75, 76, 77, 80, 81, 82, 83, 84, 85, 86, 89, 90, 91, 92, 93, 94, 95, 98, 99, 100, 101, 102

Offset

1,3

Links

Chris R. Rehmann, Table of n, a(n) for n = 1..10000

Maple

q:= n-> (l-> numboccur(l, 6)=numboccur(l, 7))(convert(n, base, 9)):
select(q, [$0..102])[];  # Alois P. Heinz, Mar 25 2026

Mathematica

Select[Range[0, 120], DigitCount[#, 9, 6]==DigitCount[#, 9, 7]&] (* Harvey P. Dale, Jul 10 2019 *)

Prog

(MATLAB) x = 0:21515; d = dec2base(x, 9)-'0'; a = x(sum(d==6, 2)==sum(d==7, 2)); disp(regexprep(num2str(a), ' +', ', ')) % Chris R. Rehmann, Mar 25 2026

Crossrefs

Cf. A007095, A039390.

Cf. A039110.

Cf. A039083, A039089, A039095, A039100, A039104, A039107.

Sequence in context: A039200 A039150 A008539 * A047602 A039076 A037471

Adjacent sequences: A039106 A039107 A039108 * A039110 A039111 A039112

Keyword

nonn,base,easy

Author

Olivier Gérard

Status

approved