OFFSET
1,9
COMMENTS
Conjectures: Is a(n) monotonically increasing for n > 4? Does lim{n->inf} a(n)/a(n+1) = 0.5? - Ryan Propper, Jan 04 2008
EXAMPLE
a(4)=1 because the 4th prime 7 appears once in 2^2^4 + 1 = 65537.
PROG
(PARI) {mcf(d, n)=my(c=0, m=10^#digits(d)); while(n>0, if(n%m==d, c++); n\=10; ); c }
a(n) = {mcf(prime(n), (2^2^n+1))}
CROSSREFS
KEYWORD
base,more,nonn
AUTHOR
Jason Earls, Dec 16 2002
EXTENSIONS
More terms from Ryan Propper, Jan 04 2008
a(24)-a(26) from Donovan Johnson, Nov 17 2008
Correction of a(26). a(27)-a(31) from Robert Gerbicz, Nov 24 2010
STATUS
approved