A031492 Numbers whose base-9 representation has the same number of 0's as 8's.

1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 19, 20, 21, 22, 23, 24, 25, 28, 29, 30, 31, 32, 33, 34, 37, 38, 39, 40, 41, 42, 43, 46, 47, 48, 49, 50, 51, 52, 55, 56, 57, 58, 59, 60, 61, 64, 65, 66, 67, 68, 69, 70, 72, 89, 91, 92, 93, 94, 95, 96, 97, 100

Offset

1,2

Links

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

Mathematica

Select[Range@100, (s=#; Differences[Count[IntegerDigits[s, 9], #]&/@{0, 8}]=={0})&] (* Giorgos Kalogeropoulos, Jul 04 2021 *)
Select[Range[100], DigitCount[#, 9, 0]==DigitCount[#, 9, 8]&] (* Harvey P. Dale, Mar 09 2023 *)

Prog

(MATLAB)
a = NaN(10000, 1); k = 0; j = 1;
while any(isnan(a))
    d = dec2base(k, 9)-'0';
    if sum(d==0)==sum(d==8)
        a(j) = k; j = j+1;
    end
    k = k+1;
end
disp(regexprep(num2str(a'), ' +', ', ')) % Chris R. Rehmann, Mar 05 2026

Crossrefs

Cf. A007095, A039364.

Cf. A039077, A039078, A039079, A039080, A039081, A039082, A039083.

Cf. A039090, A039096, A039101, A039105, A039108, A039110, A039111.

Sequence in context: A039155 A007094 A000433 * A350076 A379396 A393981

Adjacent sequences: A031489 A031490 A031491 * A031493 A031494 A031495

Keyword

nonn,base

Author

Clark Kimberling

Status

approved