A039125 - OEIS

A039125

Numbers whose base-10 representation has the same number of 1's and 7's.

0, 2, 3, 4, 5, 6, 8, 9, 17, 20, 22, 23, 24, 25, 26, 28, 29, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 43, 44, 45, 46, 48, 49, 50, 52, 53, 54, 55, 56, 58, 59, 60, 62, 63, 64, 65, 66, 68, 69, 71, 80, 82, 83, 84, 85, 86, 88, 89, 90, 92, 93, 94, 95, 96, 98, 99, 107, 127, 137

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

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

MATHEMATICA

Select[Range[0, 200], DigitCount[#, 10, 1]==DigitCount[#, 10, 7]&] (* Harvey P. Dale, Dec 05 2014 *)

PROG

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

CROSSREFS

Sequence in context: A305734 A002242 A317676 * A203616 A274049 A038101

Adjacent sequences: A039122 A039123 A039124 * A039126 A039127 A039128

KEYWORD

nonn,base,easy

AUTHOR

Olivier Gérard

STATUS

approved