A135955 - OEIS

%I #3 Mar 31 2012 10:22:06

%S 83621143489848422977,6161314747715278029583501626149,

%T 289450641941273985495088042104137,5193981023518027157495786850488117,

%U 66233869353085486281758142155705206899077

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

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

%t 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

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

%K nonn

%O 1,1

%A _Artur Jasinski_, Dec 08 2007