OFFSET
1,2
COMMENTS
a(9001) has 1001 digits. - Michael S. Branicky, Mar 19 2024
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..9000
FORMULA
a(n) = fabab... where f = ((n-1) mod 9) + 1 and ab = 01 if f is odd else 10 and has floor((n-1)/9)+1 digits. - Michael S. Branicky, Mar 19 2024
EXAMPLE
After 90 the next member is 101 which differs at each digit position.
PROG
(Python)
def a(n):
q, r = divmod(n-1, 9)
d, f = q+1, r+1
return int((str(f) + "0"*(f%2) + "10"*(d//2))[:d])
print([a(n) for n in range(1, 51)]) # Michael S. Branicky, Mar 19 2024
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Mar 13 2002
EXTENSIONS
a(48) and beyond from Michael S. Branicky, Mar 19 2024
STATUS
approved