OFFSET
0,1
FORMULA
d*2, beginning with 3.
EXAMPLE
Read a(3)=12 which produces a(4)=2 because 1*2=2 and a(5)=4 because 2*2=4
Now read a(4)=2 which produces [a(5) is already written] a(6)=4 because 2*2=4.
MATHEMATICA
Flatten[ NestList[ Function[x, Flatten[ FromDigits /@ 2IntegerDigits[ x]]], 3, 14]] (* Robert G. Wilson v, Feb 21 2005 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Alexandre Wajnberg and Eric Angelini, Feb 18 2005
EXTENSIONS
More terms from Robert G. Wilson v, Feb 21 2005
STATUS
approved