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Number of terms with n digits in A154780.
1

%I #5 Jul 14 2012 11:32:22

%S 1,1,2,2,4,6,12,17,34,55,98,161,288,448,811,1265,2145,3425,5860,9305,

%T 15384,24690,40445,64715

%N Number of terms with n digits in A154780.

%C Does the ratio of consecutive terms, a(n+1)/a(n), tend to a finite limit?

%o (PARI) print1("1,",#last=[35]); for(d=3,30, new=[]; forprime( p=0,9, for(k=1,#last, isprime((last[k]^2\10^d+t*last[k]/5)%10) & new=concat(new,last[k]+p*10^(d-1)))); print1(",",#last=new))

%K nonn,base

%O 1,3

%A _M. F. Hasler_, Jan 24 2009