OFFSET
1,2
COMMENTS
Numbers with only digits 0,1,2,3,5,6,7,8.
So this is a subsequence of A039145 with same number of 4 and 9: zero. - Michel Marcus, May 17 2014
EXAMPLE
4 in Roman numerals is IV (5 - 1) and so 4 is not in this sequence.
PROG
(PARI) isok(n) = my(v = vecsort(digits(n))); ! (vecsearch(v, 4) || vecsearch(v, 9)); \\ Michel Marcus, May 19 2014
(Python)
from itertools import count, islice
from sympy.ntheory.factor_ import digits
def A242491_gen(): # generator of terms
return (int(''.join(str(d) if d<4 else str(d+1) for d in digits(n, 8)[1:])) for n in count(1))
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
J. Lowell, May 16 2014
STATUS
approved