A039089 Numbers whose base-9 representation has the same number of 1's and 7's.

0, 2, 3, 4, 5, 6, 8, 16, 18, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 32, 33, 35, 36, 38, 39, 40, 41, 42, 44, 45, 47, 48, 49, 50, 51, 53, 54, 56, 57, 58, 59, 60, 62, 64, 72, 74, 75, 76, 77, 78, 80, 88, 106, 115, 124, 133, 142, 144, 146, 147, 148, 149, 150, 152, 160, 162

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..5000

Mathematica

Select[Range[0, 500], DigitCount[#, 9, 1] == DigitCount[#, 9, 7] &] (* G. C. Greubel, Nov 01 2017 *)

Prog

(PARI) isok(n) = my(d=digits(n, 9)); #select(x->(x==1), d) == #select(x->(x==7), d); \\ Michel Marcus, Nov 01 2017

Crossrefs

Sequence in context: A102516 A156981 A271949 * A044956 A297139 A044818

Adjacent sequences: A039086 A039087 A039088 * A039090 A039091 A039092

Keyword

nonn,base,easy

Author

Olivier Gérard

Status

approved