A171668 Fibonacci numbers sandwiched between two numbers having same number of divisors.

34, 55, 144, 10946, 46368, 196418, 9227465, 1134903170, 4052739537881, 117669030460994, 420196140727489673, 12200160415121876738, 3928413764606871165730, 22698374052006863956975682, 68330027629092351019822533679447, 13598018856492162040239554477268290

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..70

Mathematica

f[n_]:=Length[Divisors[n]]; lst={}; Do[fi=Fibonacci[n]; If[f[fi-1]==f[fi+1], AppendTo[lst, fi]], {n, 170}]; lst

Crossrefs

Cf. A000005, A000045, A005237, A005238, A067889, A171666, A171667.

Sequence in context: A051969 A241520 A067243 * A259676 A227304 A055574

Adjacent sequences: A171665 A171666 A171667 * A171669 A171670 A171671

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Dec 14 2009

Extensions

a(15)-a(16) from Amiram Eldar, Aug 08 2024

Status

approved