OFFSET
1,2
COMMENTS
1. If p is a prime > 5 then there exists a d such that a(p) = concatenation of '1' d times where p = k*d + 1 for some k. a(p)= (10^d -1)/9 < ={10^(p-1)- 1}/9.
2. a(n) = 0 if n = 10k, 16k or 25k.
REFERENCES
Amarnath Murthy, "On the divisors of the Smarandache Unary sequence," Smarandache Notions Journal, Volume 11, 1-2-3, Spring 2000.
LINKS
Bo Gyu Jeong, Table of n, a(n) for n = 1..1000
Bo Gyu Jeong, C++ code which computes A083117 and this sequence
PROG
(Python)
from itertools import count
def A083116(n):
if not (n%10 and n%16 and n%25): return 0
for l in count(1):
k = (10**l-1)//9
for a in range(1, 10):
if not (m:=a*k)%n:
return m # Chai Wah Wu, Jan 23 2024
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Apr 23 2003
EXTENSIONS
a(21) corrected by Bo Gyu Jeong, Jun 12 2012
More terms from Bo Gyu Jeong, Jun 13 2012
STATUS
approved