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A177874
The number of decimal digits in the Lucas-Lehmer number A003010(n).
2
1, 2, 3, 5, 10, 19, 37, 74, 147, 293, 586, 1172, 2343, 4686, 9371, 18742, 37484, 74967, 149933, 299866, 599731, 1199461, 2398922, 4797844, 9595688, 19191376, 38382751, 76765501, 153531001, 307062002, 614124003, 1228248006, 2456496012
OFFSET
0,2
FORMULA
a(n) = A055642(A003010(n)).
MATHEMATICA
a=Sqrt[6]; Table[a=a^2-2; Length[IntegerDigits[a]], {n, 0, 20}]
IntegerLength/@NestList[#^2-2&, 4, 33] (* Harvey P. Dale, Jan 19 2018 *)
PROG
(Magma) T:=[ n eq 1 select 4 else Self(n-1)^2-2: n in [1..24] ]; [ #Intseq(T[n]): n in [1..#T] ];
CROSSREFS
Cf. A003010.
Sequence in context: A078715 A166874 A046630 * A293353 A293328 A064236
KEYWORD
nonn,base
AUTHOR
G. L. Honaker, Jr., Dec 13 2010
EXTENSIONS
a(21) - a(24) from Klaus Brockhaus, Dec 13 2010
a(25) - a(32) from D. S. McNeil, Dec 13 2010
STATUS
approved