A135955 (Nonprime Fibonacci numbers with prime indices, A050937) which have exactly 4 prime factors.

83621143489848422977, 6161314747715278029583501626149, 289450641941273985495088042104137, 5193981023518027157495786850488117, 66233869353085486281758142155705206899077

Offset: 1

Author

Artur Jasinski, Dec 08 2007

Keywords

• nonn

Comments

Conjecture: All numbers in this sequence are products of four sums of two squares.

Crossrefs

Cf. A000045, A001605, A050937, A075737, A090819, A134787, A134851, A134852, A135953, A135954, A135956, A135957.

Programs

Mathematica

k = {}; Do[If[ !PrimeQ[Fibonacci[Prime[n]]], c = Length[FactorInteger[Fibonacci[Prime[n]]]]; If[c == 4, AppendTo[k, Fibonacci[Prime[n]]]]], {n, 1, 50}]; k