cp's OEIS Frontend

A350867 Non-palindromic numbers k for which d(k) = d(R(k)), where R(k) is the reversal of k and d(k) is the number of divisors of k.

%I A350867 #40 May 13 2025 18:08:18
%S A350867 13,15,17,24,26,31,37,39,42,51,58,62,71,73,79,85,93,97,107,113,115,
%T A350867 117,122,123,129,143,149,155,157,158,159,165,167,169,177,178,179,183,
%U A350867 185,187,199,203,205,221,226,246,264,265,285,286,288,294,302,311,314,319
%N A350867 Non-palindromic numbers k for which d(k) = d(R(k)), where R(k) is the reversal of k and d(k) is the number of divisors of k.
%H A350867 Michael S. Branicky, <a href="/A350867/b350867.txt">Table of n, a(n) for n = 1..10000</a>
%e A350867 264 and 462 are non-palindromic and also d(264) = 16 = d(462), and so both are members.
%o A350867 (PARI) isok(k) = my(R = fromdigits(Vecrev(digits(k)))); R != k && numdiv(R) == numdiv(k);
%o A350867 (Python)
%o A350867 from sympy import divisor_count as d
%o A350867 def ok(k): Rk = int(str(k)[::-1]); return Rk != k and d(k) == d(Rk)
%o A350867 print([k for k in range(320) if ok(k)]) # _Michael S. Branicky_, Feb 20 2022
%Y A350867 Cf. A000005 (d), A004086 (R).
%Y A350867 Intersection of A029742 (non-palindromes) and A062895 (d(R(k)) = d(k)).
%K A350867 base,nonn,easy
%O A350867 1,1
%A A350867 _Daniel Tsai_, Feb 18 2022