OFFSET
1,2
EXAMPLE
19 is in the sequence because (phi(19))^2 + phi(19) + 1 = 18^2 + 18 + 1 = 343, which is a palindrome.
MAPLE
rev:=proc(n) local nn: nn:=convert(n, base, 10): add(nn[nops(nn)+1-j]*10^(j-1), j=1..nops(nn)) end: with(numtheory): a:=proc(m) if rev(phi(m)^2+phi(m)+1)=phi(m)^2+phi(m)+1 then m else fi end: seq(a(m), m=1..3500); # Emeric Deutsch, Apr 30 2006
MATHEMATICA
Select[Range[3000], PalindromeQ[EulerPhi[#]^2+EulerPhi[#]+1]&] (* Harvey P. Dale, Jan 16 2024 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 24 2006
EXTENSIONS
More terms from Emeric Deutsch, Apr 30 2006
STATUS
approved