OFFSET
1,1
COMMENTS
Partial sums of a(n+1) is the smallest palindromic prime containing exactly 2 more digits on each end than the previous term, with a(n) as a central substring. Can this partial sum ever be a palindromic prime?
FORMULA
a(n) = SUM[i=1..n] A047076(i).
EXAMPLE
a(8) = 2 + 30203 + 133020331 + 1713302033171 + 12171330203317121 + 151217133020331712151 + 1815121713302033171215181 + 16181512171330203317121518161 = 16183327444272811414262846321 is prime
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jonathan Vos Post, Apr 25 2010
STATUS
approved