A085631 - OEIS

A085631

Let b(n)=product of exponents of prime factorization of n. Sequence gives palindromes n such that b(n) is also palindromic and sets a new record.

%I #12 Dec 15 2017 17:36:26

%S 1,4,8,252,2112,4224,8448,29592,6547456,27011072,291080192,

%T 276444444672,2789387839872,6399369639936,631367020763136,

%U 2306938998396032

%N Let b(n)=product of exponents of prime factorization of n. Sequence gives palindromes n such that b(n) is also palindromic and sets a new record.

%C No more terms < 1.45*10^14. - _David Wasserman_, Feb 07 2005

%C a(17) > 10^18. - _Donovan Johnson_, Mar 26 2010

%e a(9)=6547456 because it is a palindrome and 6547456 = 2^11*23*139 and

%e 11*1*1=11 a palindrome.

%Y Cf. A005361.

%K base,nonn

%O 1,2

%A _Jason Earls_ and _Amarnath Murthy_, Jul 10 2003

%E More terms from _David Wasserman_, Feb 07 2005

%E a(15)-a(16) from _Donovan Johnson_, Mar 26 2010