A335001 Integers m such that d(F(m)) = d(L(m)) where d is the number of divisors function, F(n) and L(n) are respectively the n-th Fibonacci and n-th Lucas numbers.

1, 4, 5, 7, 10, 11, 13, 14, 17, 18, 26, 46, 47, 58, 73, 77, 85, 89, 103, 107, 121, 139, 167, 179, 181, 187, 205, 221, 233, 241, 247, 253, 257, 262, 269, 273, 281, 293, 295, 317, 329, 335, 337, 341, 371, 377, 397, 407, 409, 427, 442, 454, 466, 491, 506, 563, 611

Offset: 1

Author

Michel Marcus, May 19 2020

Keywords

• nonn

Comments

Numbers m such that A063375(m) = A272377(m).

It appears that this is a subsequence of A335002, so that terms also satisfy omega(F(m)) = omega(L(m))

Links

• Amiram Eldar, Table of n, a(n) for n = 1..87
• Prapanpong Pongsriiam, Fibonacci and Lucas Numbers which have Exactly Three Prime Factors and Some Unique Properties of F18 and L18, Fibonacci Quart. 57 (2019), no. 5, 130-144.

Crossrefs

Cf. A000005, A000032, A000045, A063375, A272377, A335002.

Programs

PARI

lucas(n) = fibonacci(n+1)+fibonacci(n-1);
isok(m) = numdiv(fibonacci(m))==numdiv(lucas(m));