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A085557
Numbers that have more prime digits than nonprime digits.
5
2, 3, 5, 7, 22, 23, 25, 27, 32, 33, 35, 37, 52, 53, 55, 57, 72, 73, 75, 77, 122, 123, 125, 127, 132, 133, 135, 137, 152, 153, 155, 157, 172, 173, 175, 177, 202, 203, 205, 207, 212, 213, 215, 217, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232
OFFSET
1,1
COMMENTS
Begins to differ from A046034 at the 21st term (which is the first 3-digit term).
LINKS
EXAMPLE
133 is in the sequence as the prime digits are 3 and 3 (those are two digits; counted with multiplicity) and one nonprime digit 1 and so there are more prime digits than nonprime digits. - David A. Corneth, Sep 06 2020
PROG
(PARI) is(n) = my(d = digits(n), c = 0); for(i = 1, #d, if(isprime(d[i]), c++)); c<<1 > #d \\ David A. Corneth, Sep 06 2020
(Python)
from itertools import count, islice
def A085557_gen(startvalue=1): # generator of terms
return filter(lambda n:len(s:=str(n))<(sum(1 for d in s if d in {'2', '3', '5', '7'})<<1), count(max(startvalue, 1)))
A085557_list = list(islice(A085557_gen(), 20)) # Chai Wah Wu, Feb 08 2023
KEYWORD
nonn,easy,base
AUTHOR
Jason Earls, Jul 04 2003
STATUS
approved