

A118841


Numbers n such that ceiling(phi^n) is prime.


1




OFFSET

1,2


COMMENTS

a(7) if it exists is greater than 250000.  Mark Rodenkirch, Feb 22 2020


LINKS

Table of n, a(n) for n=1..6.
Eric Weisstein's World of Mathematics, PhiPrime


PROG

(PARI) c(n) = 3*fibonacci(n1) + fibonacci(n2) + (n % 2); \\ A169986(n) for n >= 1
for(n=1, 10^7, if(ispseudoprime(c(n)), print1(n, ", ")))
\\ Joerg Arndt, Feb 22 2020


CROSSREFS

Cf. A118842, A001606.
Sequence in context: A122774 A274166 A189740 * A126294 A339973 A224912
Adjacent sequences: A118838 A118839 A118840 * A118842 A118843 A118844


KEYWORD

nonn


AUTHOR

Eric W. Weisstein, May 01 2006


EXTENSIONS

a(7)a(8) from Charles R Greathouse IV, Jul 30 2011
a(9)a(11) from Charles R Greathouse IV, Aug 01 2011
Incorrect a(7)a(11) removed by Mark Rodenkirch, Feb 22 2020


STATUS

approved



