OFFSET
1,1
COMMENTS
The corresponding primes are 131, 137, 139, 251, 257, 373, 379, 491, 499, 1193, 2341, 2347, 2357, 4621, 6883, 22511, ...
EXAMPLE
2517 is in the sequence because prime(2517) = 22511 and the prefix 251 is in the middle of the decimal expansion of 22511.
11689716 is in the sequence because prime(11689716) = 211689719 and the prefix 1168971 is in the middle of the decimal expansion of 211689719.
MATHEMATICA
lst={}; Do[a=IntegerDigits[Prime[n]]; b=Length[a]; c=IntegerLength[(n-Mod[n, 10])/10]; If[EvenQ[b-c]&&FromDigits[Take[a, {(b-c)/2+1, (b+c)/2}]]==(n-Mod[n, 10])/10, AppendTo[lst, n]], {n, 26, 5*10^7}]; lst
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Michel Lagneau, May 27 2014
STATUS
approved