|
Search: id:A057755
|
|
| |
|
| 1, 1, 2, 3, 5, 10, 20, 39, 78, 155, 309, 617, 1234, 2467, 4933, 9865, 19729, 39457, 78914, 157827, 315653, 631306, 1262612, 2525223, 5050446, 10100891, 20201782, 40403563, 80807125, 161614249, 323228497, 646456994, 1292913987, 2585827973
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
REFERENCES
|
John H. Conway and R. K. Guy, The Book of Numbers, Copernicus, an imprint of Springer-Verlag, NY, 1995, page 139.
|
|
LINKS
|
Eric Weisstein's World of Mathematics, Fermat Number
|
|
FORMULA
|
a(n) = floor(lg(F_n)+1) (F_n is the n-th Fermat number) [From Ivan Panchenko (panchenko.ivan1(AT)gmail.com), Sep 06 2009]
|
|
EXAMPLE
|
a(6) = 20 because 2^(2^6) + 1 = 18446744073709551617 which is a twenty digit number.
|
|
MAPLE
|
seq(length(2^(2^n)), n=0..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 20 2008
|
|
MATHEMATICA
|
Table[ Floor[ 2^n * N[ Log[ 10, 2 ], 24 ] + 1 ], {n, 0, 43} ]
|
|
CROSSREFS
|
Cf. A000215.
Sequence in context: A093785 A105369 A047101 this_sequence A076834 A023170 A125312
Adjacent sequences: A057752 A057753 A057754 this_sequence A057756 A057757 A057758
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 30 2000
|
|
|
Search completed in 0.002 seconds
|
