A006938 Convert the last term from decimal to binary! (Formerly M4814)

3, 11, 1011, 1111110011, 1000010001110100011000101111011

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).

Links

Table of n, a(n) for n=1..5.

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

For initial terms 2 through 12 see A008559, A006938, A260025, A260024, A260026, A260027, A260028, A260029, A008559 (again), A006938 (again), A260030 respectively.

Sequence in context: A344946 A368618 A374718 * A124984 A287432 A353085

Adjacent sequences: A006935 A006936 A006937 * A006939 A006940 A006941

Keyword

nonn,base

Author

N. J. A. Sloane

Extensions

a(1)=3 added by N. J. A. Sloane, Jul 14 2015

Status

approved