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.

13, 15, 17, 24, 26, 31, 37, 39, 42, 51, 58, 62, 71, 73, 79, 85, 93, 97, 107, 113, 115, 117, 122, 123, 129, 143, 149, 155, 157, 158, 159, 165, 167, 169, 177, 178, 179, 183, 185, 187, 199, 203, 205, 221, 226, 246, 264, 265, 285, 286, 288, 294, 302, 311, 314, 319

Offset: 1

Author

Daniel Tsai, Feb 18 2022

Keywords

• base
• nonn
• easy

Examples

			264 and 462 are non-palindromic and also d(264) = 16 = d(462), and so both are members.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005 (d), A004086 (R).

Intersection of A029742 (non-palindromes) and A062895 (d(R(k)) = d(k)).

Programs

PARI

isok(k) = my(R = fromdigits(Vecrev(digits(k)))); R != k && numdiv(R) == numdiv(k);

Python

from sympy import divisor_count as d
def ok(k): Rk = int(str(k)[::-1]); return Rk != k and d(k) == d(Rk)
print([k for k in range(320) if ok(k)]) # Michael S. Branicky, Feb 20 2022