A114843 Indices of Fibonacci numbers with 4 distinct prime factors.

20, 24, 27, 28, 32, 52, 55, 74, 77, 85, 87, 91, 93, 97, 115, 123, 143, 146, 149, 157, 161, 163, 178, 187, 197, 209, 211, 214, 215, 221, 223, 239, 242, 249, 262, 269, 283, 287, 307, 311, 313, 321, 334, 349, 379, 391, 393, 409, 421, 453, 487, 493, 499, 523, 581, 586, 617, 641, 647, 677, 691, 707, 709, 787, 794, 811, 823, 839, 853, 859, 887, 907, 913, 929, 941, 953, 1031, 1049, 1063, 1093, 1229

Offset: 1

Author

Shyam Sunder Gupta, Feb 19 2006

Keywords

• nonn

Examples

			a(1)=20 because the 20th Fibonacci number consists of 4 distinct prime factors (i.e., 6765 = 3 x 5 x 11 x 41).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..88
• Blair Kelly, Fibonacci and Lucas Factorizations.

Crossrefs

Cf. A114823-A114826, A114836-A114841.

Column k=4 of A303217.

Programs

PARI

n=1;while(n<350,if(omega(fibonacci(n))==4,print1(n,", "));n++)

Extensions

More terms from Ryan Propper, Apr 26 2006

a(56)-a(81) from Max Alekseyev, Aug 18 2013