A039381 Numbers whose base-9 representation has the same nonzero number of 3's and 7's.

34, 66, 115, 147, 196, 228, 250, 259, 268, 286, 295, 304, 306, 307, 308, 310, 311, 312, 314, 322, 358, 390, 439, 471, 520, 552, 570, 579, 588, 594, 595, 596, 598, 599, 600, 602, 606, 615, 624, 642, 682, 714, 763, 795, 844, 876, 925, 957, 979, 988, 997, 1015, 1024, 1033, 1035, 1036, 1037, 1039, 1040, 1041, 1043, 1051

Offset

1,1

Links

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

Mathematica

okQ[n_]:=Module[{dc3=DigitCount[n, 9, 3]}, dc3>0&&dc3==DigitCount[n, 9, 7]]
Select[Range[2000], okQ] (* Harvey P. Dale, Nov 26 2010 *)

Prog

(MATLAB) x = 0:1051; d = dec2base(x, 9)-'0'; s1 = sum(d==3, 2); s2 = sum(d==7, 2); a = x(s1==s2 & s1>0); disp(regexprep(num2str(a), ' +', ', ')) % Chris R. Rehmann, Apr 12 2026

Crossrefs

Cf. A007095, A039100.

Cf. A039378, A039379, A039380, A039382.

Cf. A039363, A039370, A039376, A039385, A039388, A039390.

Sequence in context: A395991 A115159 A125192 * A043204 A043984 A259962

Adjacent sequences: A039378 A039379 A039380 * A039382 A039383 A039384

Keyword

nonn,base,easy

Author

Olivier Gérard

Extensions

More terms from Harvey P. Dale, Nov 26 2010

Status

approved