A242835 Primes formed by the initial digits of the decimal expansion of the square root of 5.

2, 223, 22360679774997896964091

Offset: 1

Author

Felix Fröhlich, May 23 2014

Keywords

• nonn
• base
• bref

Comments

There is no other term with less than 111 digits.

a(4) has 1506 digits. - Hiroaki Yamanouchi, Sep 11 2014

Examples

			Decimal expansion of sqrt(5) begins: 2.23606797749978969640917366... - _Wesley Ivan Hurt_, May 26 2014
		

Crossrefs

Cf. A005042, A007512, A072952, A119343.

Cf. A002163 (Decimal Expansion of sqrt(5)).

Programs

Mathematica

Module[{d=25,f},f=RealDigits[Sqrt[5],10,d][[1]];Select[ Table[ FromDigits[ Take[f,n]],{n,d}],PrimeQ]] (* Harvey P. Dale, Oct 29 2020 *)