|
Search: id:A080176
|
|
|
| A080176 |
|
Base-10 Fermat numbers: 10^(2^n) + 1. |
|
+0
2
|
|
| 11, 101, 10001, 100000001, 10000000000000001, 100000000000000000000000000000001, 10000000000000000000000000000000000000000000000000000000000000001
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
COMMENT
|
As for standard Fermat numbers 2^(2^n) + 1, a number b^m + 1 (with b > 1) can only be prime if m is a power of 2. On the other hand, out of the first 12 base-10 Fermat numbers, only the first two are primes.
|
|
FORMULA
|
a(0)=11, a(n) = (a(n-1)-1)^2 + 1
|
|
CROSSREFS
|
Cf. A000215, A019434, A080174, A080175.
Sequence in context: A052075 A070854 A075767 this_sequence A064490 A080439 A098153
Adjacent sequences: A080173 A080174 A080175 this_sequence A080177 A080178 A080179
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Jens Voss (jens(AT)voss-ahrensburg.de), Feb 04 2003
|
|
|
Search completed in 0.002 seconds
|
