

A151900


Singular indices in A139206.


2




OFFSET

1,1


COMMENTS

Definition: Singular indices in A139206 are numbers n for which there exists no prime p such that p!/n1 is prime or, if such a prime p exists, it is very big.
I frown upon this "definition" and the notion of "very big", especially because A139206(24)=3361 seems to be considered to be "very big"(?!)... A more rigorous definition should be given.  M. F. Hasler, Nov 03 2013


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

From M. F. Hasler, Nov 03 2013: (Start)
The first unknown term in A139206 is A139206(19), which is (if it exists) larger than 25000. Therefore a(1)=19.
The term A139206(24)=3361 is "quite large", therefore a(2)=24.
The next unknown term in A139206 is A139206(53), which is also larger than 25000, if it exists. Therefore a(3)=53. (End)


CROSSREFS

Cf. A139074, A139206, A151901.
Sequence in context: A297575 A093020 A105504 * A087951 A175356 A134255
Adjacent sequences: A151897 A151898 A151899 * A151901 A151902 A151903


KEYWORD

hard,more,nonn


AUTHOR

Artur Jasinski, Apr 12 2008


EXTENSIONS

Edited, corrected and extended by M. F. Hasler, Nov 03 2013


STATUS

approved



