OFFSET
0,2
COMMENTS
Arises in the analysis of a certain 2-D cellular automaton (see A169707).
a(46) = 1729 is also the Hardy-Ramanujan number. - Omar E. Pol, Feb 17 2015
It appears that sums of two successive terms give the numbers greater than 1 in A194811. - Omar E. Pol, Mar 05 2015
LINKS
FORMULA
G.f.: 1/(1-x^2) + (4*x/(1-x))*mul(1+x^(2^k-1)+2*x^(2^k),k=1..oo).
From Omar E. Pol, Feb 18 2015: (Start)
It appears that:
a(2^k-2) = (2^k-1)^2, if k >= 1.
a(2^k-1) = 4^k, if k >= 1.
a(2^k) = 4^k + 5, if k >= 1.
(End)
CROSSREFS
KEYWORD
nonn,look
AUTHOR
N. J. A. Sloane, Aug 30 2014
STATUS
approved