

A230020


Composite numbers n such that sigma(n)  reversal(n) = 1.


2




OFFSET

1,1


COMMENTS

It is obvious that palindromic primes (palprimes) are all prime solutions of the equation sigma(x)reversal(x) = 1. The next term is greater than 73*10^7.


LINKS



EXAMPLE

sigma(9599) = sigma(29*331) = 30*332 = 9960 = reverse(9599)+1.


MATHEMATICA

Do[a=FromDigits[Reverse[IntegerDigits[n]]]; If[a>n && DivisorSigma[1, n] a == 1, Print[n]], {n, 730000000}]


CROSSREFS



KEYWORD

nonn,base,more


AUTHOR



EXTENSIONS



STATUS

approved



