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A064236
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Number of decimal digits in A001042.
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2
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1, 1, 1, 1, 2, 3, 5, 10, 19, 38, 76, 152, 303, 605, 1210, 2420, 4839, 9678, 19355, 38709, 77417, 154834, 309667, 619333, 1238665, 2477330, 4954660, 9909319, 19818638, 39637275, 79274549
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,5
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LINKS
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MATHEMATICA
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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 *)
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PROG
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(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)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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