OFFSET
1,2
COMMENTS
EXAMPLE
The first terms, alongside their binary representation and the divisors encoded therein, are:
n a(n) bin(a(n)) First divisors
- ----- --------------- --------------------
1 1 1 1
2 50 110010 1, 2, 5
3 52 110100 1, 2, 4
4 104 1101000 1, 2, 4
5 114 1110010 1, 2, 3, 6
6 3460 110110000100 1, 2, 4, 5, 10
7 12298 11000000001010 1, 2, 11, 13
8 29442 111001100000010 1, 2, 3, 6, 7, 14
9 31368 111101010001000 1, 2, 3, 4, 6, 8, 12
PROG
(PARI) is(n) = my (b=binary(n)); b==vector(#b, k, n%k==0)
(Python)
from itertools import count, islice
def A320673_gen(startvalue=0): # generator of terms >= startvalue
return filter(lambda n:not any(int(b)==bool(n%i) for i, b in enumerate(bin(n)[2:], 1)), count(max(startvalue, 0)))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Oct 19 2018
STATUS
approved