cp's OEIS Frontend

A085924 If k = product (p_i)^(r_i), where p_i are primes in increasing order, then k is a member if concatenation of r_i as decimal numbers forms a palindrome.

%I A085924 #15 Dec 15 2017 17:41:10
%S A085924 1,2,3,4,5,6,7,8,9,10,11,13,14,15,16,17,19,21,22,23,25,26,27,29,30,31,
%T A085924 32,33,34,35,36,37,38,39,41,42,43,46,47,49,51,53,55,57,58,59,61,62,64,
%U A085924 65,66,67,69,70,71,73,74,77,78,79,81,82,83,85,86,87,89,90,91,93,94,95
%N A085924 If k = product (p_i)^(r_i), where p_i are primes in increasing order, then k is a member if concatenation of r_i as decimal numbers forms a palindrome.
%C A085924 2^10 is the first member of A072774 that is not in this sequence. - _David Wasserman_, Feb 11 2005
%C A085924 Note: A242414 is a new version of this sequence, which does not have this defect. - _Antti Karttunen_, May 30 2014
%C A085924 42 is the first member of this sequence that is not in A236510. - _N. J. A. Sloane_, Jan 27 2014
%e A085924 15 is a member as 15 = 3^1*5^1 and 11 is a palindrome.
%e A085924 90 is a member as 90 = 2^1*3^2*5^1 and 121 is a palindrome.
%e A085924 84 is not a member as 84 = 2^2*3^1*7^1, 211 is not a palindrome.
%e A085924 1024 is not a member as 1024 = 2^10, and decimal number string "10" is not a palindrome.
%Y A085924 Differs from a non-base version of this sequence, A242414, in that here terms like 1024 are excluded (please see the Example section), while in latter, A242414(691) = 1024.
%Y A085924 Cf. A072774, A103653, A236510.
%K A085924 base,less,easy,nonn
%O A085924 0,2
%A A085924 _Amarnath Murthy_ and _Jason Earls_, Jul 12 2003
%E A085924 More terms from _David Wasserman_, Feb 11 2005
%E A085924 Dependence on decimal number system highlighted and a link to the new version, A242414, added by _Antti Karttunen_, May 30 2014