OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Perfect Power.
EXAMPLE
a(4) = 4 since prime(4) = 7 = 1+1+1+4.
a(8) = 3 since prime(8) = 19 = 1+9+9.
a(11) = 2 since prime(11) = 31 = 4+27.
a(14) = 2 since prime(14) = 43 = 16+27.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Apr 08 2005
EXTENSIONS
Corrected and extended by Ray Chandler, May 05 2005
STATUS
approved