OFFSET

1,1

COMMENTS

The sequence appears to be infinite, but I have no proof.

There are many consecutive elements in the sequence: (13,14)-(36,37)-...-(12777,12778)-...(30236,30237)-...

EXAMPLE

a(10)=37 since 5+phi(37)^2=1301 is a prime.

MATHEMATICA

Select[Range[250], PrimeQ[EulerPhi[#]^2+5]&] (* Harvey P. Dale, Jun 07 2011 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Carmine Suriano, Sep 14 2010

STATUS

approved