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

1,2

Comments

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

It appears that this is a subsequence of A335001, so that terms also satisfy omega(F(m)) = omega(L(m))

Links

Table of n, a(n) for n=1..57.

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.

Prog

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

Crossrefs

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

Sequence in context: A278335 A243300 A231575 * A368659 A153085 A047259

Adjacent sequences: A334998 A334999 A335000 * A335002 A335003 A335004

Keyword

nonn

Author

Michel Marcus, May 19 2020

Status

approved