OFFSET
1,1
LINKS
Robert Israel and K. D. Bajpai, Table of n, a(n) for n = 1..10000 (first 506 entries from K. D. Bajpai)
EXAMPLE
53 is prime and 35 + 1 = 36 = 6^2.
827 is in the sequence because it is prime and reversal(827) + 1 = 728 + 1 = 729 = 27^2. - K. D. Bajpai, Jul 03 2014
MAPLE
Nd:= 4: # to get all entries with up to 2*Nd digits
revdigs:= proc(x) local F, n, i;
F:= convert(x, base, 10);
n:= nops(F);
add(10^(n-i)*F[i], i=1..n);
end:
Sq:= remove(t -> (t mod 10 = 1), {seq(i^2, i=1..10^Nd-1)}):
A:=map(proc(s) local r; r:= revdigs(s-1); if isprime(r) then r else NULL fi end proc, Sq); # Robert Israel, Jul 03 2014
MATHEMATICA
Select[Prime[Range[10^5]], IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[#]]] + 1]] &] (* K. D. Bajpai, Jul 03 2014 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Claudio Meller, Oct 30 2009
EXTENSIONS
More terms from K. D. Bajpai, Jul 03 2014
STATUS
approved