OFFSET
1,1
COMMENTS
A subsequence of the reversible primes (A007500).
Inspired by Aug. 2016 SeqFan discussion about arrays of primes.
Questions: 1) What is the largest N X N square of decimal digits whose rows, columns and main diagonals are (non-palindromic) terms of this sequence?
The digits of each remaining smaller square formed by removing the outermost layer of digits of a given such square also form terms of this sequence. 2) What is the maximum number of distinct terms of this sequence that can appear in the rows, columns and diagonals of a single N X N square and of all its nested (N-2) X (N-2), (N-4) X (N-4), ..., 2 X 2 or 1 X 1 squares?
3) What is the maximum number of such consecutively nested squares comprised in total of only distinct primes?
EXAMPLE
9791 is a term because 9791, 79, 1979 and 97 are all prime numbers.
CROSSREFS
KEYWORD
nonn,base,fini
AUTHOR
Rick L. Shepherd, Aug 21 2016
STATUS
approved