OFFSET
0,5
MATHEMATICA
a[ 1 ] = 1; a[ 2 ] = 2; a[ n_ ] := a[ n ] = a[ n - 1 ]^2 - a[ n - 2 ]^2; Table[ Floor[ N[ Log[ 10, a[ n ] ], 36 ] ] + 1, {n, 1, 31} ]
IntegerLength[#]&/@(RecurrenceTable[{a[1]==1, a[2]==2, a[n]==a[n-1]^2- a[n-2]^2}, a, {n, 31}]) (* Harvey P. Dale, Dec 27 2013 *)
PROG
(PARI) a(n) = if(n<2, n+1, a(n-1)^2-a(n-2)^2); l(n) = ln=0; while(n, n=floor(n/10); ln++); return(ln); for(n=0, 21, print(l(a(n))))
(Haskell)
a064236 = length . show . a001042 -- Reinhard Zumkeller, Dec 16 2013
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jason Earls, Sep 22 2001
EXTENSIONS
More terms from Robert G. Wilson v, Sep 24 2001
STATUS
approved