A171666 -id:A171666 - cp's OEIS frontend

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

Vladimir Joseph Stephan Orlovsky, Dec 14 2009

nonn

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

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

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

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

A171669 Pell numbers sandwiched between two numbers having same number of divisors.

Original entry on oeis.org

12, 5741, 2744210, 15994428, 21300003689580, 723573111879672, 1111984844349868137938112, 293199986221627877463941823267862, 9960168529794442859224531878561050, 27749033099085295754434173207717704165, 66992092050551637663438906713182313772

Offset: 1

Vladimir Joseph Stephan Orlovsky, Dec 14 2009

nonn

Amiram Eldar, Table of n, a(n) for n = 1..19

Cf. A000005, A000129, A005237, A005238, A067889, A171666, A171667, A171668.

f[n_]:=Length[Divisors[n]]; a=1;b=0;c=0;lst={};Do[c=a+b+c;If[f[c-1]==f[c+1],AppendTo[lst,c]];a=b;b=c,{n,80}];lst

a(8)-a(11) from Amiram Eldar, Aug 08 2024

cp's OEIS Frontend

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

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica

Extensions