OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[600], DigitCount[#, 7, 3]==DigitCount[#, 7, 4]>0&] (* Harvey P. Dale, May 14 2022 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
STATUS
approved