OFFSET
1,1
COMMENTS
The next term (a(5)) has 100 digits. - Harvey P. Dale, Feb 28 2012
The number of digits of a(n) are 2, 4, 10, 31, 100, 330, 1093, 3628, 12049, 40023, 132951, 441651, 1467130, 4873698, 16190071, 53782249, 178660761, ... - Robert G. Wilson v, Jul 10 2013
log(a(n))/log(a(n-1)) = ~log_2(10) = A020862. - Robert G. Wilson v, Jul 10 2013
REFERENCES
C. Pickover, Mazes for the Mind, St. Martin's Press, NY, 1992, p. 350.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
MATHEMATICA
NestList[FromDigits[IntegerDigits[#, 2]]&, 11, 4] (* Harvey P. Dale, Feb 28 2012 *)
PROG
(Python)
def agen(an):
while True: yield an; an = int(bin(an)[2:])
g = agen(3)
print([next(g) for i in range(5)]) # Michael S. Branicky, Mar 11 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
a(1)=3 added by N. J. A. Sloane, Jul 14 2015
STATUS
approved